Yup! there is a possibility that one can earn more with bitcoin than your own salary and I think if you can trade well with bitcoin you can surely profit with it, even if trading is risky cause your invested money could go negative, there is a way in knowing the movement of the commodities and currencies and he can surely watch closely the movement of it!
i believe that we can earning a living with bitcoin and i think in out there, many people will start this and have to proof it but they keep silence and not tell everybody, but i am sure that few of them will tell their story to make earning a living with bitcoin.
Well they will keep on silence because some bitcoin users don't want others to know their ways in profiting over bitcoin, and they would just keep it to themselves, and other people just wants to be anonymous because bitcoin is really a secrecy currency and most people like it that way!