Unlike Microsoft, Sony has made no known efforts to make PS3 games playable on the PS4. This is likely because the PS3 had very unorthodox hardware that made it a pain to develop for and thus emulate, and in addition, their sales are so phenomenal that they don't need to make that sort of effort. However, the PS5 will most likely run on what is essentially the same standardized AMD hardware in the PS4 but with some more power. With that being the case, it's quite possible that the whole PS4 library will be available at launch on the PS5 with no emulation software needed. Do you think the PS5 will be backwards compatible or that it will simply be like any other console generation?