I think it's possible nowadays to earning a living just with bitcoins, but that's need real investment and good budget to start with
Nowadays you can easily exchange your bitcoins into fiat and consume it for earning your living
I saw a topic which states 37$ per trade. He earns $37 on selling single bitcoin, So if he regularly sells a minimum of 5 bitcoin it is much enough to earn around 200$. This will surely earn him a living.