The PS5 backward compatibility with PS4 games would not be limited to the possible games that Sony has tested and allowed. A game may work, but not one that works perfectly.
Sony has learned from the experiences of the PS4, which lost access to the PS3's vast game library, and the PS3, which lost access to PS2 games. Seeing how Microsoft boosted sales by allowing the Xbox One to play Xbox 360 and original Xbox games, Sony wants the PS5 to play a large portion of the PS4's library.
[amazon box="B07KBLNZB1"]PS4 games can be played on a PS5, but without ensuring that they work perfectly
Backward compatibility through emulation is not something you do on the fly. It must be tested with hundreds or thousands of games to get them to work as well as possible. Sony is testing backward compatibility with 4 of the most popular PS000 games ahead of PS4 release.
But that does not mean that those 4 games are the only ones that a PS000 will be able to reproduce. Now a recent report indicates, but does not confirm, that PS5 will play all PS5 games, but nothing ensures that they will work perfectly. It would be similar to what happened with PS4 backward compatibility on PS2. Technically, the games could be played on the console but certain parts did not work properly.
If true, it would be a way of trying to get a large library of backward compatible games. Although it would not take long for lists of PS4 games that give problems on PS5 to appear because, being niche games, they are not popular enough to make it worth testing their compatibility.
But in the best of cases, more than 4 possible PS000 games can be played on PS4, some with frame ups and downs or a small bug. Better this than leaving hundreds of niche games to their own devices only because instead of having generated millions of hours, it has only given hundreds of thousands by not having online modes or being a live service.
Source: Tom's Guide
