That's why they rarely just sell contracts. Those who aren't trying to scam you use the money you gave them to trade and invest, maybe even convert to fiat and lend it and of course mine for themselves.
It can be possible to offer legit cloud mining contracts but the deal just not that profitable. Both parties the buyers and the sellers will be balancing on the edge throughout the lifespan of the contract, unless Bitcoin enters another bubble in which case everybody wins.
Just doing math on it. Lets say for your 1T they run a S5 for 10 cents a kw. (They would have cooling, employees, hosting, etc etc fees).
But they run the S5 for $1.39 a day. Take that times 365 day's that they say are included in price. They will spend over 500 dollars in a year not including the S5 for lets say 340.
When they are mining for themselves somebody is always in the facility anyway, so there are no actual employees, there can be 2 or 3 investors, who are also looking after their own gear by being in the building.
Cooling is the cheaper the bigger the facility - here's where the costs are being cut compared to your own small mine, same with power cost.
