It depends. 

STEEM's worth is astonishing on some under-developed countries which may make Steem is a good income source to live. For my case, it is not feasible to live with post rewards.

On the other hand, I believe, STEEM earnings should be seen as an additional source of income/investment for users. If every user sees STEEM like a source of income to live, then there will be constant SELL pressure in the markets, which will result a zero value.

Only thing, I can quit my job for STEEM would be going into the top20 witness. A top20 witness is making a good amount of money daily that I would focus full-time on STEEM by giving back to my witness voters and community.