If I could achieve better earnings with Bitcoin, then I would give up my part time job and go full time on BTC. The problem is, that you would still earn more with a paid job nowadays (if in USA), than you would with Bitcoin currently unless you are lucky. I don't even see mining as profitable at all, with all this difficulty increase, you will have to upgrade your miner before you could even reach ROI. Not to mention the electricity costs as well.