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.
Exactly setting up a business with bitcoin acceptance right now don't give much of profit, because only very few were aware of digital currency. Possibly users could earn good when enormous adoption happens due to the bitcoin's growing potential.