I still play PS1 games every so often. And no, it wouldn't matter now because I have a PS2. But someday we won't. And I only hope the PS4 and PS5 continue to be backwards compatible, 'cause someday I'm going to want to play FF7 again.
And you're not going to be able to just slap on an EE chip because Sony's not just going to leavean empty spot on the board with leads for you. They're going to redesign the board accounting for the fact that its not there anymore.
Correct me if I'm wrong(which I may well be) but isn't this how the PS2 already works? The PS1 CPU is still there but routes it's graphics though the PS2 graphics chip? And isn't that what they plan to do with the PS3? Or am I way off base?