There is an alternative way to look at Dresden, and as starting points I'll cite [1] and [2].

By early 1945, the allies (or, specifically, the RAF and the USAAF) had got excessively good at bombing cities. The original intent, both by the RAF and the USAAF, had been "precision" bombing of strategic targets. But in the early years of the war, this simply was not possible.

First the RAF, then the USAAF, found they could not bring sufficient aircraft to the target area and then deliver sufficient munitions into onto the target to reliably do strategic damage. By day the loss rates were horrific and the effect insufficient, by night the loss rates were still unsustainable and the effect even more limited. The problems were of enemy aircraft, enemy anti-aircraft fire, poor navigation, poor bomb aiming, the wrong munitions, the list went on.

The RAF switched to area bombing of cities not because they thought it was the best option, but because it was the only option. The USAAF continued with a policy of targeting industrial and military facilities, later bolstered by massive fighter support, but successes were few and far between. The second Schweinfurt raid was dubbed "Black Thursday" with good cause; it caused appalling US losses and very limited impact on German manufacturing.

So far, so bad. But as the war continued, the situation changed. Long-range escort fighters could accompany bombers deep into Germany and, with the P51D, could meet German fighters on equal terms. Sophisticated radio equipment, initially Gee but later Oboe and its successor Gee-H, together with radar such as H2S, allowed accurate navigation and even blind bombing at night or in poor weather. Organisational techniques such as Pathfinders and master bombers (or the competing ideas of low-level marking by 5 Group) leveraged these techniques. Behind it was allied air superiority, bordering on supremacy, which meant that the aircraft could operate pretty much at will.

This all meant that by 1945, large formations could concentrate on a small target and pour hundreds of tonnes of explosives, sequenced with HE to de-roof and disrupt followed by incendiaries to ignite the wreckage, onto targets anywhere in Germany, with loss rates of 2% or less. The RAF or the USAAF could not just annihilate a city, they could choose the time and precise centre of the destruction

So yes, there is a question as to whether the bombing of Dresden had a strategic effect: perhaps it did, although it will be hard to discern in the general collapse of Germany at the time. The real question, which Jones asks, is why no-one noticed that if you can utterly destroy a specified point target, you can do the same to oil, or manufacturing, or transport centres. They started out with strategic targets. They found they couldn't hit them sufficiently hard to destroy them. They switched to bombing cities which initially they couldn't destroy either, but they could at least do some slight damage. They got better, and better, and better at doing that, to the point they could bomb cities devastatingly accurately and with massive warloads. In parallel, bombing by specialised units was able to strike specific targets (V2 and V3 sites, viaducts, U Boat pens, etc).

So why, in December 1944, did they not switch the main force back to the strategic targets they had failed to strike in 1942 and 1943, using the new techniques and air superiority to do then what they couldn't do two years earlier?

It's a great "what if?" By 1945 air power had the capability to strike strategic targets, but instead was deployed to crush targets which basically didn't matter.

[1] Jones, Reginald Victor. Most secret war. Penguin UK, 2009.
[2] Overy, Richard, and R. J. Overy. Why the Allies won. WW Norton & Company, 1997.