PS3 Games on PSN

Jut wondering why doesn't Sony add all the PS3 games that have come out for the PS3 on the store? would love a digital version of ff 13 and so 4. they have ff 13-3 and lr but i want 13 digital?

I´ve asked myself the same question and still have no answer, there are a lot of PS2 games but no other games some of which are even exclusives like Resistance FOM 1,2 & 3 , Uncharted 1 and 2 to mention a few. On the other hand, the store still has DLCs that have absolutely no reason for being there like MP maps for Resistance, the servers for those games were shut down a long time ago.