There is no commercially exploitable banana for export that we know of yet. Going from Gros Michel to Cavendish required rethinking how we farm, harvest, ship, ripen, sell bananas. Cavendish could simply not be shipped like Gros Michel before.
You said yourself that Cavendish is a "boring" banana. This might be true. But all the great, tasty, small bananas you are talking about cannot be shipped anywhere by the means we know of today. That is, every market outside of the banana growing regions cannot have these, they will be mush, rotten or inedible once they reach the shelves.
Apart from that, I agree, we will (hopefully) eventually find a replacement and adjust our methods and taste. I'm all open for new banana tastes. But the problem is real, the economy as a system (farmers, logistics, consumer) does not know of an alternative so far. Even if you think different.
But I guess you could be very rich if you have an alternative ready and are willing to transport it and selling it in EU/US/Canada.