Can you be a miner as a day job?  Yes I suppose.  Issues like power availability (after all you can't pull more than 1400 watts from a 15A circuit), a place to keep the equipment cool and safe, and the ability to constantly monitor would be some of the few I see.

I prefer to make a hobby out of it.  I have 10 high end GPUs running on 2 rigs.  Already made enough bitcoin (via nicehash) to pay for half the cost.  I know earnings will diminish, but for this year I expect to have it all paid off and more.  I then sell off the equipment and either restart with better equipment or call it quits.  But doing it full time?  Nah.