These venues do not have enough liquidity to attract Trump and his cronies. There might be people lower down the food chain who are taking advantage though.
Donald Trump Jr. is a paid advisor and investor to Kalshi and Polymarket. Why bother betting if they will just give you cash for having the right name.
Granted, the son whose wedding you skip has got to be lower down the food chain.
Don Jr made bets on these same sites, as did so many WH personnel.