Odds of Hanging On
Taxi driving has a high turn-around rate. Not very many people will be career taxi drivers. The more experience you have, the easier it'll be to pave a way for yourself in this career—or to pave your way into a career that doesn't involve looking at so much pavement.
If you live in a city, your odds of making a career of taxiing are much better than they'd be outside of it. People will almost always need taxis in urban areas, so as long as you can keep your cool under pressure, there's a good chance you can hang in there.