To say gpu mining was not profitable is really not accurate. Your poor decision making was unprofitable. Any business that had the returns you did would be a good investment. To stop mining so soon after investing so much is just foolish.
Well I think the overall story is that one can't just rely on whattomine and focus on just mining profitability. There are soo many traps in crypto and decision making is the biggest factor weather you make money or not.
In this case it was crypto lending that got him but their are other things like exchange hacks or you getting phished and hacked. You can really lose years worth of mining revenue.
I still would not try to compare other businesses to crypto mining as they are really different. To say mining is easy and your lucky to have a good return is quite untrue, Equipment cost in crypto needs to be replaced far more frequently compared to other businesses. Running ongoing electric cost eats into majority of the revenue. At the end of the day crypto mining your making very small profits if any. I see a lot of miners here have a very hard time expanding or wanting to expand. In the normal world businesses have more opportunity to expand and grow their business. It's a tough game to play.
I hear entrepreneur running gold mines investing millions mentioned it was more profitable to actually buy the gold than to run a gold mine operation. Same is true with crypto for most people.