But you still believe it's sufficiently profitable to mine BTC yourself as that was my actual question next to the belated conclusion that cloud mining has died. Because if even regular mining becomes a challenge, or when mining can only be done by hardware manufacturers and electricity companies, then we'll have to say goodbye to Proof of Work I fear.

Doesn't this raise the question whether BTC mining is profitable at all when you continuously have to upgrade your hardware to keep up with the rest?

The only way cloud mining can be profitable is with a lifetime contract where you reinvest half your gains every month to keep up with the difficulty increases. GM will probably follow suit at some point. So, that's the end of cloud mining. But isn't this also the end for proof of work mining in general? I understand it takes about 10 months of mining for an Antminer S9 to pay for the cost of the machine, while in about a year or so you have to buy a newer model. It doesn't look like it's going to be profitable any time soon. And that spells disaster for Bitcoin itself and all other PoW coins.