How many miles does a 50 CC scooter typically have before it dies assuming it's well taken care of?

Most of the cycles in the group that you are reffering to do not get to wear out the engine, Most of them have another cause of discontinued use. Such as, The carboretor gives too much problem, Or the electrical system gives problems, Or the mechanical parts wear out and are too expensive to replace compared to the value of the bike. As for the answer to your question, A well maintained bike will be good for about 3000 miles or more. I would not think you could ever get to 10,000 miles.