I think earning a bitcoin is definitely possible but it is not very likely right now. There are not many opportunities out there for you to get a living with bitcoin. Because bitcoin is not well known thats why it is good if you threat bitcoin as your other source of income
It is hard to make a living out of bitcoins, but it is certainly possible.
With dedication and some hard work you can make it, setting up a business is probably the best way to get profit.