Those games were out of style???
Well...yeah.  For a long time, this stuff was considered junk.  You couldn't give it away.  JAMMA cabs went for like $50 for fully working games, and they'd toss classics on the burn pile.
Consoles?  Fu-ged-abou-dit.  Commanded measley prices.
Now that this stuff has come back in style, it's commanding high prices.  I only wish I'd gotten into games ten years ago, when I had money, and did nothing except piss it away.