My PS3 had backwards compatiblity....
And I really didn't take much advantage of it. I think I played one PS2 game on it. I don't play too many games multiple times. On the PS3 I think I've only played the inFamous games more than once.
1. I don't think I feel too happy having to rebuy them on a ps4.
2. I dont' think I have a large need to buy them on my ps4
3. When I buy a ps4 I'll put the ps3 in the bedroom which will add a bluray player there, so i'll still have my PS3 if I need it (Sorry Original Xbox, you're getting voted off the island).