Good point--I certainly didn't understand how much TLC this one would need when I first planted it, which is why this thread got started in the first place! Hopefully now that I've learned a few things and the trees have gotten bigger, I'll be able to get them through a few winters (and summers) and buy them enough time to build up some toughness.
As far as mangoes go, if the seed I recently planted (in a pot) actually sprouts and survives, I plan to keep it in a container its whole life. Even after trying covers, a thermostat-controlled electric heater, and a light bulb on an extension cord, something has always gone wrong--each of my in-ground attempts at growing mangoes have eventually ended in funerals.