It is way better if you just do Bitcoin on the side as an secondary income.
Someone can rely on bitcoin if they know they can earn a good enough income out of it like the ones who are having exchanges or bitcoin casinos or other similar websites which are generating some good amount of bitcoins for them, so such people wont be worried if they leave their jobs for getting full time on bitcoin.
Some people can do that, but most users are just small fishes like me.
It would be cool if I find a way that would pay me about as mauch as my daytime job, but I doubt I will find one I would consider safe enough.
I'm relatively sure that the site owners earn relatively fast more than enough for a lifetime. They had the idea & the skills at the right time.
I want that too...