I think another problem is that dictators are not generally altruistic or humanitarian, and are often not concerned with establishing and overseeing a sustainable nation-state.
Again I'm reminded of the
bust-out metaphor. This involves finding something with established value, such as a profitable business with good credit, and extracting as much value as possible over the short term, without any thought of keeping the business solvent. The line of credit is exploited to line the owner's pockets, and then the business is discarded once the debt comes due and is not repaid.
You'd think that dictators would be smarter than this, or at least show some skill and foresight in setting up their exit strategy. But that often does not seem to be the case. Many dictators seem to be getting bad information because they're asking bad questions. Instead of asking, "how can I perpetuate a healthy nation with me at its head indefinitely?", they're asking, "how can I and my cronies extract more wealth from this failed state before the wheels finally come off?"