Mining is a lot of fun and I was in a situation where I was able to put over $15,000 into mining a couple of years ago but things turned from "This is a no brainer" to "Oh Shit" real fast. The one thing I did right is stick with GPU rigs. That way you have an exit plan. Asics become paper weights and about the only way those make sense is if you are in China pulling them off the line and popping them in a warehouse with super low cost power or if you have a free power situation somehow. I would love to get back into mining on a very large scale but I would need investors to back me and be able to survive the crypto down turns. I had a 3 year time horizon with my GPU rigs but only survived 1.5 years before I had to sell them. I couldn't run them profitably so the equipment was sitting. Sad story. But if a person had $0.04 / kilowatt hour power or lower and was able to survive 5 to 10 years and be very strategic I think it could be a profitable situation. Other things could help immensely. For instance if someone on the team had mad coding skills like whoever developed a GPU miner for STEEM. If you have that kind of talent on the team and had the money for the equipment you could really clean house. Because really when it boils down to it there are people running optimized miners that aren't publicly available. This went on with Monero for a long time. There was a Claymore miner and 5% of what was mined was going back to the developer who made the miner. That setup was also able to mine Bytecoin and all the other CryptoNote coins. That guy got rich no doubt about it. Props to him though. I wish I was that wicked smart.