Xbox’s Backwards Compatibility is definitely a big deal; but as someone who loves old games as a concept and has never thrown out a console, it’s not as big a selling point as you would think/ hope.
I personally wanted to try some of the PS2/PS3 only games and didn’t have a PS3, so I bought one used a while back. I probably only logged maybe 10 hours in it before getting completely side tracked by my backlog of modern games. And while I know that’s anecdotal evidence, it really seems like the allure of classic games might not be enough of a selling point.
This is something I think Xbox had the right idea about. While BC is very useful in concept, there aren’t so many classic games that would draw people away from modern games; so you only have to support those few games.
With that in mind, I think Sony could offer BC for their relevant PS2/ PS3 exclusives since they would only need to guarantee emulator performance for a much smaller number of games. I don’t think it’s likely for Sony to do this until they are no longer the dominant console, though, as they can make more money selling their PS3 subscription service.
From a game presentation standpoint, BC is a huge issue and I would personally love to see it happen for the PS5 (and I’d like to see it expanded to all games for the Xbox as well); but I doubt there would be much return on investment for developing the BC features, and that’s the only motivation for corporations.