It's a great question, with many different aspects why the long-term victory over Russia ended up belonging to the Bolsheviks.

Short answer: The Bolsheviks stayed in power and dominated due to a mixture of these factors: geography, power base, timing, ideology and organisation, the parochial, fragmented and uncoordinated nature of those who would oppose them, and exceptional circumstances.

Let's break these down into a bit more detail. As the below mix of factors is so interlinked, it helps to try to view the parts I've broken down as a whole.

Geography:

To start with, the Bolshevik takeover at the October Revolution quickly seems like a giant fait accompli - or even more of a bluff. At this point, the Bolsheviks' hold on power seemed just as tenuous as that of the power they had seized it from: the Provisional Government. At this point, the Bolsheviks only had definite power over the capital city: Petrograd, present-day St Petersburg.

However, to loosely paraphrase Mae West, it's not the territory in your life, it's the life in your territory. In other words, the Bolsheviks didn’t hold much territory in Russia in October 1917 - but they held the bits that mattered. So what made Petrograd so important?

Power base:

While making up a tiny, very unrepresentative proportion of Russia's population, Petrograd was a centre of industry at the time. This meant that it had the population that mattered for the Bolsheviks' worker's revolution: workers. With its calls for an 8-hour working day, most Bolshevik propaganda was aimed - and landed most effectively - at them.

While industrial workers made up just 4% of under-industrialised Russia's workforce, the muscle brought to the table by the industrial workers (not the middle class, intelligentsia, nobility or peasants) were the key ingredient for bringing the revolution about. However, note that the Bolsheviks didn’t influence all the factory workers, or even a majority of them – but they were able to influence enough to come over to their side when push came to shove.

As a power base, industrial workers were both underestimated and under-looked by other political parties at the time, who tended to focus on the vast majority of Russians: the peasants, or even smaller groups than the industrial workers, like the middle class or intelligentsia. So, to recap, the Bolsheviks held Petrograd with the help of the industrial workers they had on board. But control of one city (which was second to Moscow in terms of size and population) doesn’t in itself make a revolution. And to avoid starvation and total isolation (Petrograd does not produce enough food within the city limits to feed everyone), the Bolsheviks have to find a way to expand their very limited power. Timing would play a huge role in the takeover of power.

Timing:

Bizarrely, the clear weakness of the Bolsheviks ended up as a strength. For many Russians, the Bolshevik coup was more a blip on the radar in the capital city until elections were held for the much-awaited Constituent Assembly, which would democratically represent Russia as a parliament.

As the Bolsheviks negotiated their hold on power with the unions, such as the powerful Railway worker's union, Vikzhel (the support of which you needed if you wanted to move any number of men or materials anywhere by train), many political parties which made up the Petrograd acquiesced with the fact that the Constituent Assembly would soon be held. The Bolsheviks made the decision that the Constituent Assembly would go ahead as planned and elections were held.

Yet to cut a long story short, the Constituent Assembly was elected (with the Bolsheviks in a minority), met for a single day, and then its delegates were literally locked out of the building. Other political groups in Petrograd appeared to have neither the muscle nor will to restore it.

Ideology and organisation:

As Lenin memorably wrote: “Without [revolutionary] theory there can be no revolutionary party. [Yet] theory is a guide, not holy writ.” And to quote actual holy writ, faith without works is dead, (James 2:14-26) – a fact the Bolsheviks understood well. There were many socialists and socialist groups in Russia at the time. Yet fewer were willing to let rubber hit the road – or in other words, to be pragmatic and focus on action that comes from theory, not just theory for theory’s sake.

Many parties had their own theories and ideologies, but these theories were not always tested or communicated well, and thus couldn’t easily be followed. Starting from its roots, Bolshevik party membership had to accompanied by working for the party - you couldn’t be a member with being devoted to party work – like propaganda, agitation, fund-raising, or co-ordination.

This rule, set in place by Lenin, froze out lots of would-be members, and made the Bolsheviks smaller in numbers than they would have been with looser membership requirements. Yet this also meant they had a small, dedicated and often fanatical party faithful, instead of people who saw themselves as loose allies.

With charismatic, talented, disciplined and ruthless leaders like Lenin and Trotsky at the helm, and a well-organised Bolshevik party structure they worked with. The party was more authoritarian in structure than other parties – yet had and tolerated differences of opinion. This meant the Bolsheviks proved to be resistant from splits which had neutered so many other factions.

This focus on embodying action and military-style discipline, unusual in left-wing parties that were more commonly made up of ‘gentleman socialists’ even showed in the appearance of the Bolsheviks.

“The Bolsheviks… liked to see themselves as a military organisation,” writes Orlando Figes in his book ‘A People's Tragedy: The Russian Revolution, 1891-1924. “They dressed in macho black leather jackets and military boots, whereas most of the other political parties wore ministerial suits.”

This distinction even in dress made a marked impression on some lower, easily impressionable rank-and-file members of the party. Party worker Cecilia Bobrovskaya recalled in her Memoirs of a Rank-and-File Bolshevik with a vague sense of disapproval that Georgi Plekhanov, an earlier revolutionary, was a “well-dressed, middle-aged European, clad in a light-grey suit, brown shoes and kid gloves.”

While clothes may make the man, they don’t make the party – but not looking like the bourgeoisie you are attempting to overthrow is a step in the right direction.

The parochial, fragmented and uncoordinated nature of those who would oppose them:

At times, it appears that it wasn’t so much that the Bolsheviks won – but more that the opposition lost. Many people opposed in the Bolsheviks in an intellectual sense, but fewer had the sheer audacity of the Bolsheviks to seize the power themselves. As Lenin said: “If 10,000 nobles could rule the whole of Russia - then why not us?”

Yet holding and expanding on the power seized would prove to be a violent, vicious struggle. Several months after the Bolsheviks’ October revolution, the revolution turned into a full-scale civil war.

By this time, Russia’s opposition to the Bolsheviks was enormous – with multiple factions. The most powerful faction were the Whites, a disjointed hodgepodge of Tsarist officers and nationalists who had no real ideology or central aim, but comparatively immense military power and even military support from the West.

Then there were the Greens, who were mostly peasants didn’t want the prospect of further state control on their lives and largely wanted to be left alone, and the Blacks, a Ukrainian group of anarchists who rejected state control.

There were also minorities around Russia’s southern fringe in the Caucasus and what’s today collectively called the ‘stans who wished to defend their new-found independence.

The last three groups mentioned mostly only cared about their own spheres of influence, and had little thought about the entire former Russian empire.

In the Civil War, the Bolsheviks faced the herculean task of fighting them all – which they did. The victory was achieved by turning factory workers into soldiers, enlisting former Tsarist officers as military consultants, propaganda, and coercion and terror by the Cheka, a precursor of the KGB. As head of the newly-formed Red Army, military talent of figures like Trotsky, who would travel across the various fronts in his armoured train, out-coordinating the enemy factions.

Lastly, exceptional circumstances:

The exceptional events of the First World War would surprise even Lenin, a student of previous revolutions such as the French one. In 1913, shortly before war broke out, Lenin erroneously predicted: “The revolution won’t happen in my lifetime.”

Of course, the spiral of military blunders, royal intrigues and manipulations, such as the ‘mad monk’ Rasputin’s hold on the emotionally unstable Russian empress, and a woefully indecisive, ill-qualified Russian emperor Tsar Nicholas II attempting to lead the war at the front, would lead events to a crescendo that would have previously been hard to imagine: the seemingly spontaneous uprisings by workers in February 1917 in Petrograd, which led to the first (largely Bolshevik-less) February Revolution. The power vacuum and a weak provisional government created just the right circumstances for the seizure – and successful – hold on power for the next seven decades.