They can't grow enough even for their own people to eat decently.
The U.S. has a trade embargo on Cuban exports.
Not enough. While there are some European hotel chains there, their sales point is being a low cost alternative to PR or the Dominican Republic or the islands like Jamaica and the Caymans.
Remember, Cuba is 800 miles wide. It takes dozens of stations to cover the main markets; ground conductivity is not good. And even Cuba is moving away from AM. In smaller Caribbean nations and destinations, like Martinique and Curacao and Trinidad and Jamaica, AM has been gone for decades.