They’re not building PCs but they are buying/using laptops, and, to a lesser extent, prebuilts. I’ve also built a few gaming PCs on request from otherwise “casual” consumers though that’s a smaller portion of the market.

It's been a slow but steady transition. PC used to not even be worth big publishers' time to make a half-assed port, and now over 20 years later, in most cases, it's 50%+ of their customers and revenue.

The Switch still offers the plug-and-play experience the other consoles lost.

The other points still apply, but the Nintendo crowd doesn't seem to mind being fucked sideways.