Ah but I’m not ignoring the context. I’m expanding the context beyond “fun math puzzle” to “wow this is a game not worth playing because there’s no edge”.
Again, only applies to the non-iterated version. If you find an analog of monty hall that gives you many at-bats, play away.
"wow this is a game not worth playing because there’s no edge"
The prize is a brand new car.
The optimal strategy gives you a 2/3 chance of winning.
Over the course of your life, if whenever you have a choice to make you choose the lower probability strategy (here with the Monty Hall example it's not even an expected-value vs. variance tradeoff, switching is just all-around more optimal) you will most definitely end up worse off in the end.