Tbh, even though his talk wasn’t intended for the public, Mark Cerny really messed up from a PR perspective when he mentioned the top 100 games working.
If you go back to the comments for those articles on N4G, PlayStation fans (myself included) were hoping that he just misspoke and some were saying that BC doesn’t matter anyway. It was a confusing, borderline useless piece of information without the full context.
It wasn’t too long after that that it was clarified that “the overwhelming majority of games of PS4’s 4000+ games will work” or something like that. That also left room for some speculation as well. Ten games games not working could have been hundreds and that statement would still be true.
Then I think we eventually got the 99% figure but lacked details on how exactly it would work compared to Xbox’s implementation. We don’t know if the PS5 will get a similar framerate boost as the Series X provides on older games.