The problem is most people who game aren't "gamers". By which I mean they aren't necessarily interested in the hardware or anything else except "will this game run?".
I'd bet there is a very large market for pre-built "Fortnite battlestations" in the $500 to $700 range, a little above current-gen consoles. If that's your budget, then AMD is the obvious choice.
Is there data for that? Anecdotally, I was thinking about buying a gaming PC recently. Every single thread you find on reddit about PC gaming starts with 'don't buy pre built.' It is engrained in the gaming community at this point that pre-built wastes money to the tune of hundreds of dollars, and PCs aren't all that difficult to put together.
As it stands $500-700 gets you 1080p gaming thats better looking than current gen consoles; this is the entry level and its already several notches above APU.
But if you're reading reddit threads on this I think you're several levels removed from the average person who plays games. Sure "gamers" will read up on this and be part of the gaming community but PC games are now mass entertainment and not the niche it used to be.
Few people build their own PC. Many more play games.
For me, the "don't buy pre built" mantra essentially means "research on what you want and buy accordingly".
I have heard that there are some prebuilts that are worth it. But you won't be able to know which ones are good until you had experience building your own.
And even then, this is not 2009 anymore. Sure, you still need a new card to play everything on max settings with new games, but you can get easily get by with moderate settings.
I mean I haven't played Fortnite, but Destiny 2 is the same age (although the specs might be lower because I don't know how much the engine changed since Destiny 1) and it runs perfectly on ultra at 2560x1440 on my nearly 3 year old midrange AMD card with a 6 year old CPU.
Also what's up with kids these days not setting textures to potato mode to eke out the last FPS, like we did with Quake? :P
Most people that play current titles and invest in gaming might not care about the hardware but they aren't running on AMD APUs either they likely buy a best buy PC with a 1050 or a 1060 in it.