The article says that the guy started with $600 in 2005. Even if he doubled his money every year he would have made about $300,000. Much less than his $1bln claim.
Rule #1: Don't trade more than you can't afford to lose. And remember, chronic stress kills. Next things you might expect are lower back pain and arthritis.
Depletion is not a problem. Digital currency is just a mathematical algorithm. So it should not be difficult to replace one digital currency with another I think.