For games that require online services, this will always be an inherent issue. But for games that don't, I'm betting on emulation continuing to save the day. When the PS3 was released with its complex/novel architecture, it seemed like an emulator was highly unlikely, but look at how good RPCS3 is now.

On the Microsoft side, they've been incredibly good about first-party backwards compatibility. I bought most of my Xbox 360 games digitally, and I have been able to play them on my Xbox One, Xbox Series X, and now they are even bringing them to PC. My son and I were just playing the timeless classic NBA Jam: On Fire Edition (a 15yo game) a couple of days ago.

Emulation development will probably be significantly enhanced by the ability to use LLMs as well.