I'm sure it's possible to emulate PS2 games on PS3 just on software, but Sony needs to worry about PS3 games, not PS2 games.
I have a feeling that as long as the PS2 and its games sell well and have support Sony will disagree.
I agree that I would love to see more/all effort concentrated on my current system, but as they aren't doing that yet and as most gamers don't scour gaming blogs and news sites and may not realize their affordable 40 gb PS3 has no BC (or it was gifted to them) then I thought this could be an option, much like the PS2 HD system file.
Did the 80gb still have the GS from the PS2? If not they already have the software, they just need to put it online in an install file.
If so, I wonder if we may not start seeing occasional PS2 games for download, like PS1 games are now. I doubt we would see any dual layer DVD games, but any thing up to 2.5gb would not be an unreasonable download size. It would be really sweet if they could make them PSP compatible as well. I think this will be determined by how successful Microsoft's XBox downloads are, especially considering that all of the 360's still have BC and it would now make more sense for Sony to try it than it does Microsoft.
Not that I am saying I demand they do it or even think they should. As I said, I would prefer to see more focus on my PS3, especially as it seems to be difficult to program for (or devs are whiners, one of the two) and production times are taking longer on games that fully utilize the BD format.
Since I have a 60gb none of this affects me as if I really want a PS2 game I can just go find it used for about $10. And if I really want to put PS2 games on my PSP (trying to buy one today) I can just mod it or whatever it takes.
I'm just speculating on what Sony could do for gamers who inadvertently wind up with no BC when they do want it. As I said, it has almost no effect on me.
That said, I would be all over updating certain games that previously used PS2 peripherals to work with PS3 peripherals. GH2 and the Time Crisis games come to mind.