You were all pretty quick to shoot me down but I can't recall anybody else suggesting any realistic alternatives...
You omit to include the fact that to make any money at all in the housing market an investor has to raise a deposit, and then pay the mortgage. Our 18 y/o may not be able to do either for a while. His only chance of ever earning a decent income might be to advance his qualifications by going to university, in which case he'll be in debt at the end of his degree course.
Makes joining the Navy all the more attractive, as he can gain a degree for free during his training and service.