ww1 for a long time was one big stale mate with it being incredibly hard to even make it to an enemy trench

The premise here is incorrect - it was very rarely the case that an attacking side could not make it to the enemy front line trench, however, once in the enemy front lines trenches, the lack of radios meant that a General had no way of directing his troops. He could not gain a clear idea of what was happening on the ground, and had no way of knowing where or when to deploy reserves to exploit successes.

Thus, although an attacker could ‘break in’ there was no real way to ‘break out’

By 1917, battles were therefore fought according to strict timetables and increasingly with limited and defined objectives to prevent the attacking infantry outrunning their own artillery.

Sometimes, for example during some phases of 3rd Ypres, these objectives could be as little as 500m distant. The aim being to take a sector of enemy trench and then inflict losses on the enemy as he attempted to counter-attack. This was purely attritional warfare – it would take a very long time to get to Berlin in such a fashion..

This meant that maximum daily advances were limited to 5 or 6km – about the effective range of most field guns. Even with tanks and cavalry, in a few rare occasions more could be achieved, such as the 8th August 1918 at Amiens (10km advance), or the advance to the Selle in late 1918 (14km advance), but these rates of advance were not sustainable or repeatable.

As they were in WWI, tanks were not a decisive weapon.

They were incredibly fragile machines. Not only were they highly prone to mechanical failure, they struggled to cross boggy ground and would often get stuck in craters. For example, in the battle of Messines Road Ridge, the tanks couldn't get forward at all due to the heavy rainfall the night before. Note that this didn't stop the attack being a huge success - sophisticated infantry/artillery co-operation and careful planning being sufficient for a 'bite and hold' break-in operation.

Being very large and slow, they were easy targets for artillery and the armour was thin enough to be punctured by over-powered rifle rounds (at least until the Mk IV appeared in mind 1917).

What's more, they were absolutely dreadful to fight in. There was no separate engine compartment until the Renault FT came along, and no provision for fume extraction. Temperatures could exceed 40 degrees, carbon monoxide, petrol and cordite fumes would choke the crew, the noise was so extreme that the driver had to signal gear changes by hammering on the hull with a spanner. Crude armour plate was prone to spalling from small arms fire, so little flakes or paint and steel would fly off the hull. The crew had to wear a special helmet with goggles and chain mail face covering because if one of those flakes got in your eye or if you breathed it in, you would be in very severe discomfort indeed. Conditions in the tanks were so bad, crews often needed several days to recover themselves from a single days' action.

They were also hideously prone to fire. The British used specialist recovery crews to extract the charred corpses of the crew. They were forbidden to talk about their work to anyone else.

The actual contribution that tanks made to individual battles is often hard to determine. For example, Cambrai saw the first mass use of tanks, but it also saw the first use of an entirely predicted artillery bombardment, which meant the element of surprise returned to the battlefield and that the artillery fire plan was exceptionally effective.

Even when mobile warfare had resumed, it was difficult to integrate tanks with armoured cars and cavalry.

Armoured cars could advance faster on road than tanks or cavalry, but could not advance at all off road, while the cavalry complained that the tanks could not keep up with them, and the tanks complained that the cavalry were too vulnerable to artillery

Realistically, the breaking of the deadlock had more to do with more flexible, squad-based infantry tactics, as well as advances in artillery including larger proportions of heavy guns, trench mortars, instantaneous fuses, vastly improved calibration techniques, and the ability to fire ‘off map’ i.e. with no registering fire.

Tanks in WWI were therefore of marginal battlefield value - they were a useful adjunct to the increasingly sophisticated infantry and artillery tactics but not decisive in their own right

Sources:

• Artillery in the Great War – Sanders and Marble

• Band of Brigands – Campbell

• To Win a War – Terraine

• British Cavalry on the Western Front 1916-1918 - Kenyon