I don't think so. That would be a terrible idea from a business point of view, Sony will actually want to give its costumers a reason to buy a PS5 besides the same games with better graphics. I agree that the system architecture will allow for a smoother transition than ever between generations and probably for backwards compatibility too, that would be smart for Sony because PS4 users will see value on the fact that they would be able to just carry over all of their games to PS5 and Sony would be able to just keep selling their existing PS4 games to new PS5 users or PS5 users who had a PS4 but didn't play some games, all without needing to invest further on re-releasing those games.
I also think Sony will want to push VR as an optional, but crucial feature of the PS5. The first PSVR that comes out later this year already has some pretty nice tech specs (the most important being 120hz refresh rate), so it would be smart if Sony allowed the PS5 to be backwards compatible with it since it's an expensive accessory and people would be pissed off if the were required to buy a newer one. The PSVR could eventually receive a revision specific for the PS5 with a higher resolution and some refinements, but that would be optional, just like buying a newer TV is. Sony could even offer the two versions by the PS5 gen like it does with its headsets.
