That's correct, it is just rare due to the ubiquity of the fungus, which has spread far and wide and maintains a continuous low level in the former growing environments.

Many of the other cultivars spoil quickly, making them difficult to ship over the ocean, pipe through the distribution system, sit on grocery shelves, then keep fresh for a few days in your home.

If no commercially viable cultivar survives then bananas will become a luxury fruit, flown in on a daily or weekly basis with all the cost increases that implies.