Although others have responded I'll chime in.
I'm pretty sure we all have "real jobs" here, and I agree with others that this is primarily a hobby.
Building and tweaking miners is a ton of fun and even though this is a hobby, its one that's been paying dividends.
Exactly.
Plus when you think about it these GPUs weren't built for mining, they were built for gaming and graphics. A lot of us here would have nice GPUs anyway for those reasons, so why not make a little money back for hardware you already have?
Heck part of the reason I am mining on a AMD 460 isn't because its a max ROI card, but because I know next year I was going to buy one (or a rebranded AMD 560) for a HTPC anyway. Every single card I have bought for mining either I have plans for down the road, will be easy to sell even when other people are dumping cards, or I got so cheap that I easily made more back than I got it for mining.
Plus I don't know about the rest of yall but I think its cool being part of what Ethereum might be. Bitcoin was always kinda boring to me as a concept (I am not a drug dealer), and too much of cryptocurrency is focused towards a tunnel vision about what Bitcoin ended up being used for (such as Zcash or Monero helping drug dealers). Ethereum COULD (no guarantees) be a new way of having complicated organizations without the need for a state entity to enforce fair play between the stakeholders in such an organization (kinda like what Bitcoin is but beyond drug dealing). The reason why the DAO got so much hype (and crashed so hard) is because we as a world are getting sick of our leaders (Trump, Brexit anyone?) and are looking for the next way to organize human capital that doesn't rely the competency of a golden parachuted manager or a tenured bureaucrat. Ethereum might never get there (more likely won't), but it is a step in the path towards that sort of world. Something like Ethereum could be the basis for a true 21st century institution.
I am happy that Ethereum mining allows me to be apart of what I feel is the future. It is way cheaper than other alternatives such as buying a Tesla (or even Tesla stock).