I like Rob78's idea, but Sony wouldn't go for it. gtsa has a point too. I think Sony figured that they would offer PS2-compatibility initially, but then after more games came out, they'd drop it due to cost.
Honestly... PS2 games (graphically) suck compared to the PS3. Before I got my PS3, I hooked my PS2 up to my new 32" Toshiba flatscreen and in less than five minutes, the PS2 was back in the box it had lived in for the previous several years. It just looked horrible with such low-res graphics. It's also the reason I got a PS3 over a Wii -- why do I want to buy a "new" console with graphics basically the same as a PS2???
Since PS2s and their games are going for almost nothing on eBay, I decided to keep it. I have my PS2 hooked up in the bedroom to my little 20" flatscreen (4x3), and it looks ever so much better, probably since that TV isn't HD. It's still fun to play SSX on it.
But I have to appreciate how the guy must feel when Sony won't replace his PS3 with the same one they can't fix. And since they won't do it the way Rob78 suggested, I would hope they would at least offer him a PS3/160 with a 5yr warranty. That would be a bit more fair, I think.
Sony has an opportunity to really stand out in terms of customer service. Hopefully they'll do that.