The reason? Simple. The United States has arrest warrants against Maduro, Diosdado Cabello and other leaders for drug trafficking. A crime that would cost them a life in prison (at least) if they fell into the hands of the CIA. They would not be safe in almost any possible place of exile.
Mexico is not an option. AMLO and Sheinbaum are uncomfortable allies, but if Maduro takes refuge in their territory, they will yield to minimal pressure from the CIA to hand him over. Cuba and Nicaragua even less so. Neither Canel nor Ortega will want to have such an obvious example of a successful fall at home to copy.
