Scam might be a strong word for most of them, but it happens. Generally it is just a company or group that found out, like everyone else, that machine mining is past the profit line and will never make a black revenue stream again. So, rather than sell off the machines or trash them, they continue to mine and let their new clients foot the loss.
How would you call a company that knows the only reason they are profitable is because cryptocurrencies are going up? All these people that made money with them did so when the prices were going up. Go back a bit and read forum posts from 2014 and 2015 when cryptos were at a decline, but there were even more cloud mining companies than now. Most of them went bankrupt.
