easier examp-le.Company can use their gh/s to make 100BTC profit or it can rent ALL that gh/s.If it sells ALL their contracts (100 BTC worth) for less than 100 BTC altogether it loses money.To profit it has to rent for more than 100BTC from ALL the people buying contracts making ALL these people mine less money (less than 100BTC) than they paid for (fiat).
The only way to profit for these people is to hoard their bitcoins so they will be more valuable.
Keep in mind there are differences between a defined lump sum of currency now and an indeterminate amount of currency over a specific period of time. The seller is offloading some of his risk and uncertainty onto the buyer, as well as earning a lump sum payment in exchange for potentially greater, yet speculative, future profits. This is the service the buyer provides to the seller, which enables the buyer to potentially earn a profit. A mining contract could be considered win/win for both the buyer and seller if: the seller gains the benefit of guaranteed cash now, for reinvestment or other purposes, and reduced risk exposure to conform to their risk management strategy; while the buyer receives the seller's future mining profits, which are greater than his initial investment, as a reward for taking his income over a longer time frame with greater exposure to external risk factors.
That said, in my opinion most of the mining contracts I see are very overpriced, but I don't think it's impossible to have a successful cloud hashing business model that is not a scam.