Sure, they are selling shovels in the new Gold Rush.
I starts cloud-mining BTC last November. Now, returned more that 200%, but mostly due to price appreciation. If the same amount of money was invested into BTC at the same time being, the current returns is about 41%. Difficulty increase with appreciation for sure, even if you have your own hardware mining.
Forget forever terms, mining hardware obsoletes (return rate < electricity price) for probably less than 1 year if the crypto mined are profitable and appreciated.