If only a single person made a bet, and if they made a max bet, the game would auto-cashout before reaching 1.67x.
I don't think that's quite correct. That
user will be auto-cashed out at 1.67x or what ever, but not the game itself. The game itself has a separate higher limit. Hence for the game limit to be hit, you generally require >= 2 whales playing at once (or it happens at a very high bust point).
And ideally, the per-game limit
never gets triggered, because it's rather shitty for players that their bets are affected by other players action (even though it doesn't change the EV, it still sucks)