...You end up a one-trick pony and you lose everything else....
What you are describing is a "mono-economy" and possibly "Dutch Disease". If your country is mainly selling oil, then you become very dependant on oil prices (and being able to pump the stuff up). I don't see how most of it relates specifically to tourism, though.
I am (in this context) more concerned with what happens to the "social glue" when there is a massive shift in control and wealth. One might say that Cubans are not particulary lucky with the current state, so things can only get better, but the same could be said for certain African and middle-eastern nations a couple of years ago as well.
When I was in Cuba some 13 years ago and told that I was a failed musician turned engineer, people looked shocked at me: how could I be so stupid. As a musician you had every opportunity at earning a decent salary, at going abroad and doing something that was generally priced in their culture. As an engineer you'd be stuck at a low pay government job.
-h