I've probably posted about this before but as a punter this was as frustrating as hell. Before reading some of the posts here back in the day I noticed that the second hand stock of a lot of chain games stores just become less and less interesting. Pretty much just kids games and sports games. But then I had a couple of experiences that would go roughly like this.
I'd find a desirable game second hand. I'd take it to the counter. The clerk's eyes would widen and they might say, "Woah, lucky for you" or "I wish I'd seen that coming in."
Then they'd get a sly look on their face. "Ah yeah, let me get it for you. Out back." Most of the games were in the drawers near the desk. But they'd disappear for a bit and then come back. "Oh sorry man. Looks like the disc / cart is missing. Oh well!"
Combine this with "scalpers" (who would either buy new desirable titles en-masse day one or grab every bargain going so they could flip them on ebay) and it started getting to the point where the more unique games could not be found.
Two things changed. First a chain of indie stores that sold music as their main product with second hand games being a sideline meaning I could find bargains. But more importantly a large record store chain started selling games and would buy in bulk and undercut the major game stores by $10. Ico was impossible to find on release at less than 150% the sale price (I found a copy eventually in a pawn brokers.) Shadow of the Colossus? Available day one in such numbers that even the richest scalper couldn't corner the market.
With those options I just stopped making going into the games chains a habit. In my eyes poor inventory management killed them over a decade ago. I can't really blame you or any other clerks who wanted to buy a bargain or do ebay flipping given the poor wage and unpaid overtime a lot of game store employees had to deal with but as a customer it was always shit seeing a wall of old FIFA / Cricket games and knowing even if I did find a Suikoden title more likely than not it would be one of the staff and not me taking it home that day.