Researchers fear that a fungus could cripple the world's banana monoculture
popsci.com
popsci.com
That being said, managing the fungal infections effectively continues to be an industry priority, as it should be.
[0] http://cwh.ucsc.edu/bananas/Site/Early%20History%20of%20the%...
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.