Which leads to a destroyed economy, see Venezuela and Greece.

Sometimes, sometimes not; it's pretty much the story of every empire that falls, too, and some.of those are spectacularly disastrous for the metropole, some not.

Venezuela and Greece are cases not only of dependence on outside actors to meet internal demands but also of the state in question being weak in comparison to the individual outside actors involved (not just the aggregate of the outside actors involved.) That probably makes a good outcome harder to achieve.