Spoken like a CHILD that hasn't seen anything of pre-industrial islands. They are not desolate, they would turn a bit more primitive and lose some of the population as the mainland infrastructure can no longer support it. This thinning would have happened long before Fallout took place, as it would be an immediate concern right after the Great War. Otherwise, there's nothing desolate or wasteland-like about them to rationalize them as the entire basis for a setting.
But islands can still be deserted which is simlear to desolate.
Wrong, a far better game. A settled village from the Vault Dewller would have made more sense, as going to a tribal state of life does nothing but allow them to be raped when someone like the Enclave comes along. About the only reason why I can see tribals being used is to drop technology down a notch at the beginning, but it didn't work too well in practice.
But a settled village would no need a GECK, and they had to be killed for the plot line to come out.