A GameStop moved in across the street from my local Play N Trade, and his sales shot up from all the referrals they give him for PS2-era stuff and earlier. It'd definitely a decently sized market.

Back in the 90s, distribution companies sold NES games in blister packs to K-Mart, all barcoded and prepped for easy sale. THAT'S the only way I'd trust GameStop to do retro games.