I feel like a some of you are stuck on Rule 2 (PC games and games for current gen consoles count if they're released after the cutoff date).
The point of the question is not to be logically consistent with whatever your definition of next gen is, it is to gauge how much you value playing contemporary games are - I just used the next gen moniker because it was most convenient and applied it as a time frame. It wouldn't be much of a question if I asked - "How much money would I need to give you to sit out the next console generation, but you can play all the PC games you want?" Shit, you'd likely have access to 90% of AAA titles released just by sticking to PC. Where's the fun in answering a question like that?
PC is a mess. You can leave it out without making an arbitrary cutoff for consoles like that. So if somebody releases one of those new retro games like you see on SNES, Dreamcast, and other retro systems, that's off limits too? That's stretching the definition of "contemporary" really thin.
And if you want to ask about contemporary games, why bring the next gen transition into it? That's a different question and when we have stuff like timed exclusives and late ports, you get weird things like the exact same game being cut off on some platforms but not on others. Going by generations instead of release dates makes it a lot more clear cut. Then you're not only cutting off dates, you're limiting actual features. No new CPUs and GPUs, no next gen SSDs, no new controllers or any other changes that next gen makes.
"How much money do you need to keep all your PS4 and other current gen games except the ones released after next gen launches?" doesn't make a lot of sense either. There's not really going to be a huge difference between a PS4 game released this year and next year. Just look at late localizations. Ys 9 was a 2019 game in Japan, but the localized release is 2021. There aren't going to be any huge differences between the PS4 releases other than the language.
