what are you talking about? of course it'll always be online. it's streaming games.
they have local emulators? there was never a ps2 emulator. the 80gb ps3 had a ps2 inside it, and the 60 gb only had the emotion engine (cpu) in it, so it's not fully software-emulated. even then, the 60gb ran into problems with a lot of ps2 games.
sony can not possibly qa all 2000+ ps2 games for compatibility, let alone games from ps1,2, 3, and beyond. that'd be stupid to do.
those ps2 games on the psn were qa'd and bugged to work on a ps3, you can't call those simply as emulation, even emulation alone is hard to pull off on different architecture.
this is the only viable solution for bc. period.