"Everyone figures that their personal decision to shop there won't make the difference between you going out of business or not, the future where Jojamart jacks the price hardly feels real to them. Between those two factors, the good feeling of having a few more G today outweighs that distant maybe-worry about the bad thing that might happen in the future."
Oliver says it so reflexively that it only occurs to him afterwards that the people here aren't making decisions using NPC algorithms, they're literal actual NPCs and don't end up with any more or less G at the end.