My impression right now is that for nVidia gamer cards are an afterthought now. Millions of gamers can't compete with every company in Silicon Valley building entire datacenters stacked with as many "GPUs" as they can find.

AMD isn't the main choice for datacenter CPUs or GPUs. Maybe for them, gamers will be a focus, and there are some real advantages with APUs. For example, you're not stuck with one particular amount of GPU RAM and a different amount of CPU RAM. Because you're not multitasking as much when gaming, you need less CPU RAM, so you can dedicate more RAM to games and less to other apps. So, you can have the best of both worlds: tons of system RAM when you're browsing websites and have a thousand tabs open, then start a game and you have gobs of RAM dedicated to the game.

It's probably also more efficient to have one enormous cooler for a combined GPU and CPU vs. a GPU with one set of heatsinks and fans and a separate CPU heatsink and fan.

External GPUs are also a pain in the ass to manage. They're getting bigger and heavier, and they take up more and more space in your case. Not to mention the problems their power draw is causing.

If I could get equivalent system performance with an APU vs. a combined CPU and GPU, I'd probably go for it, even with the upgradeability concerns. OTOH, soldered-in RAM is not appealing because I've upgraded my RAM more often than other components on my PCs, and having to buy a whole new motherboard to get a RAM upgrade is not appealing.