So Sony has recently filed a patent with algorithms galore regarding methods for rewarding trophies. There's been speculation (here's an IGN article) that this may mean it will be possible to retroactively add trophies to older games, even games from previous console/handheld generations.
Though not everyone proclaims to be a trophy skank, I'm sure the introduction of trophies to older games will significantly boost sales of PSN classic titles. I'd probably lay down the $5 or so to repurchase some of my PS1 favorites even though I still have the original discs. Sure, I'm definitely a loser for that, but there are plenty of like-minded losers out there for this to be a no-brainer for Sony.