Apple stopped supporting 32-bit apps at all on mobile with the release of iOS 11, and they announced when 10.14 was released this October that it will be the last macOS to support 32-bit code.
NVIDIA ended all support for 32-bit OSes in April, AMD ended it in October. Steam support for XP/Vista will end on Jan 1, 2019. No word from Microsoft yet on when they’re going to end support for 32-bit code, but they’re still pushing out updates for WinXP Embedded, sooo...who knows.
Skyrim was the first one I kept hearing about, because while the vanilla game can run in a 32-bit memory space, it was already close enough that patches/updates/mods pushed it to the point where people with only 4GB just couldn’t run it because it would run out of RAM, and Skyrim is almost 10yrs old. I’d say the writing has been on the wall for quite a while now.
But what's the ACTUAL number of major GAMES running 64-bit only? I hope you're right that it's most. But I don't actually know.