Earning a living with bitcoin is not a big deal. Its not possible to run a whole family, but with the earning one can fulfill one or two of the basic needs such as food, utility bills or Clothing.
I even think you can feed a whole family if you have enough bitcoins for it.
You only need the invest a lot in the beginning for sure.
Investing all your money into bitcoins at initial stage is not a wiser decision to make, if the price drops you need to suffer losses, at a moment bitcoin is taking care of extra expenses so let it be extra only.
It is very wise to not keep all your eggs in one basket. It is nice to earn some money in bitcoin and some in your own currency, just in case things go bad