Patching like Steam does is slightly more complicated on a console. With Steam, the client can know all the files it has downloaded for a game, which files were changed by which patches, which files were removed, everything, because all those files are by necessity tied to the client. On this generation of consoles, the 360 got away with a pretty simple solution by initially putting limitations on what files could be patched, since the console does not know what is on the disc. This together with patch size limitations meant the system knew about which files were replaced each time and could do a micro-Steam solution for those files.
The PS3 has had a much looser patch system since day one and it's not certain they could do the same thing, and if you've started patching games on the looser system it's impossible to tie those together into a new tighter system without breaking older patches. It should work out this generation, especially if all games are digital and they know which files have changed to offer the latest version of the game for download at all times rather than having you download an old version and patch it up to date.