I would still recognise housemates from 2001 so that BB fame could well go for years and years!
BBAU1 was MASSIVE and the housemates from that year got much more exposure than for any subsequent season purely because of the hype surrounding that first year. Most HMs from subsequent years have disappeared back to obscurity, so I think you'd have to be pretty special/popular/notorious to get lasting recognition from being on BB these days unless you plugged directly into that vehicle immediately after your spell in the show ended.