Sony would rather you rebuy the game via Now. MS went the consumer friendly route with how they implemented BC.
I think it was the tech inside the PS4.... it just cant emulate PS3.
The cpu differnces (in architecture) make it impossible probably for the hardware to do.
Its not about "consumer friendly" or not, its about "whats possible".
I dont think the PS4 is actually capable of emulating the PS3.
Necro-bump this 2020: http://gamrconnect.vgchartz.com/thread.php?id=229249
Bumb in 2021: http://gamrconnect.vgchartz.com/post.php?id=9047071