Would love it, but its not going to happen. I think the only reason we got PS4 BC is Sony panicking because of MS. It would cut into their PSNow profits too much.
The only reason why BC went away is because it wasn't feasible for PS4 to emulate PS3. PS2 BC was removed from PS3 because their solution (including the PS2's Emotion Engine inside every console) was too expensive and easily the first thing to cut when sony realised things weren't going to work at $599.
When ever its made sense console makers across the board have always opted for BC. The benefit of remasters has never outpaced the benefit of transferring your audience over to a new platform. Digital services like PS Now will always be driven by modern experiences.