Just a reminder that this isn't true if you walk into an average supermarket in Brazil. You'll find banana prata, banana nanica, banana maçã, banana ouro, banana da terra... just look at an online supermarket search [1]. And to be clear these are all bananas eaten as fruit, not plaintains or anything. Wikipedia lists even more [2].
But somehow the English-speaking world ignores their existence. And it's not like they're exotic varieties you have to hunt down in rural areas or something. They're just the standard normal variety of bananas you buy at any urban supermarket. (Same as in an American supermarket you don't expect only one type of apple, but expect to see honeycrisp, fuji, granny smith, and so forth.)