An average steam gamer has a 3-5 TFLOP 1060 rendering 1080p with a quad-core intel at 2.5GHz. A 6-core A15 (little cores are about as fast per clock as Zen 1) with a 1.3-1.5 TFLOP GPU comes quite close. If Apple wanted, they could add a magnetic dock with controls and extra battery for serious gamers too.
For something like the Apple TV (A12 isn't a slouch though no 4K gaming machine) they could offer streaming with remote rendering.
I suspect the launch 4+4 CPU with 32 or even 64-core GPU. They should sell that in a mac mini sized console with a wireless VR headset. That said, Oculus Quest 2 is quite popular and it has a Qualcomm 865 which is much slower than that A12 let alone the A15. They could definitely stomp the Ques 2 with an A15-based device and could go much farther with a M1/M2 chip.
Yes, but that's kind of the problem. The 720p phone has a lot of horsepower per pixel, but is crippled by touch controls. The Apple TV is _slower_ on a larger screen, with yet another frustrating input situation because Apple didn't put a gamepad in the package. (They don't even make gamepads! The MFi ones I bought were pure junk.) I can't imagine a more hostile environment to develop AAA games for.
If Apple goes all-in on VR, the whole VR market will benefit from greater public acceptance. But at the very best I predict it'll be like the Nintendo Wii: a few games that are extremely popular, and then it gets old.
Which is a shame because I agree that Apple is in a great position to enter the gaming market. Imagine what Nintendo could do with powerful hardware in so many hands! But by the same logic, Apple should have crushed Spotify long ago, given its mile-wide lead with the iTunes Store, and yet the nicest thing I have heard about Apple Music is that it works with other Apple stuff. I honestly don't think Apple's management understands entertainment.