Exactly, Dawdle cant forever buy used games for $40 and do nothing with them, they'd bankrupt. This is not real money multiplier (like in bank), because "new" money is not created "from air" but taken from other place.

So, for each used game bought by Dawdle either: a) Dawdle lose $40 b) Dawdle sells this game to someone (in which case this is exactly the same situation like in case of GameStop)

For Dawdle to survive amount of cash lost by unsold used games must be smaller than amount of cash earned by selling new and used games (only count margins there, not full prices).