It sounds like maybe the more cheaply sourced discs might be effected. Maybe the American pressings will start rotting, or the Working Designs games.
Personally I'm not worried about it, as I barely have any of my discs anymore, and I don't actually collect the originals for Turbo/PCE anymore.
But the sad thing is you can't just repair a rotting disc. At least I don't think so. So at some point, probably near the end of most of our lives, a number of CD games out there, and other formats too, may have bitten the dust.