Well, earning a living with Bitcoin is actually possible, but living with a job seems to be the best option. At least Bitcoin can be, at the time, considered as a secondary source, being able to make the life more comfortable.
It's possible but it doesn't guarantee a better living, there will always be some hard days when you are on bitcoin and you have no enough savings... Earning a living I think should be done on day job since it is stable and as you've said bitcoin could be a good extra help...
Earning from both is a wise thing to do, as bitcoin is too volatile so we cannot expect stable income from it so its always good to keep it as an extra income.