One of the reasons they may have done quite well is that they rigorously control who comes and goes and who is allowed to reside there.
Asylum seekers, economic migrants without jobs, aircraft hijackers and the like need not apply. Nor need those with no visible means of support. Furthermore, the islands are not part of the EU.
You may or may not agree with some of these policies, but the residents of the islands have decided that that is what they want and they seem to have done rather nicely.