So let's see, when the PS4 launches there is no BC and Sony had just launched TLOU on PS3 a few months earlier. At launch we got Knack and a Killzone game that it seems the vast majority of people did not like, 4 or 5 months later we got InFamous SS which is a great game but almost nothing else of note from first party other than a remaster of TLOU which we had to pay for until the next year and people seemed happy with that.
The PS5 launches with BC for PS4 games, many 1st party PS4 games get patches that allow for better performance on PS5. The launch PS5 games are Demon's Souls remake (PS5 exclusive), Sackboy's Adventure, Miles Morales expansion for Spider-Man as well as a remastered version of the first game which is cross gen but looks much better on PS5, within a few months we get Returnal and 7 months from launch get another AAA PS5 exclusive Ratchet and Clank. Not a whole lot to complain about there right? This was all done during a pandemic and the console sells out within minutes of being restocked everywhere. We get a preview of Horizon FW which looks incredible and people start talking up how powerful the PS5 is. When DF reacts to the video of HFW all the big cheese at DF can seem to talk about is "how is this going to run on the PS4?" and nobody is complaining much about the game being cross gen anymore. Now here we are a week later and two games we already knew were likely to be cross-gen are confirmed to be cross-gen and people start flipping their lids again.
I get it, I always wanted games to move to the new hardware right away but that really makes no sense with the bigger titles and here's why. First of all there are tens of millions of active PS4 users who still won't be able to get their hands on a PS5 until sometime next year, secondly most early gen games don't truly take full advantage of the new hardware anyway because their engines haven't been retooled to take advantage of the new hardware anyway. Anything that is 100% truly built for next gen isn't coming until 3 years or so in anyway, anything in the first two years next gen exclusive or not is more or less a last gen game dressed up.