I think the key difference is that it's "easier" to apply a meta to a RTS game. In shooters, the meta often involves quick reflex decisions, where to hide, where to shoot etc. This is hard, and requires practice. It also means there is a significant number of players not applying it, or doing so sub-optimally.

With RTS games, the metas are easier to apply. This means that, in human Vs human games, the newer players often get flattened. It also means that far more complex metas can be developed and applied.

Shooters tend to back load the difficulty curve. It's easy to get into them, and not do badly, but hard to do well. RTS games tend to front load the difficulty. You need to get over the initial hump to get "ok" with it. Once over the hump, the curve smooths off and you get good fairly rapidly.

One of the big differences between nerds and normals is that nerds enjoy punching through that wall. The difficulty is seen as a challenge, not an impediment. Most people want a faster feedback loop on the dopamine reward. FPS type games deliver that extremely well.