what people seem to forget these days is that 9 out 10 contracts give you the phone free! so really the phone companeys rope you into the contract and hope you pay enough to make a profit on the account.
so because the phone is free think about it carefully the phone is probabley worth little compared to shop prices when sold to the operator by the manufacturer probabley within your first 3 payments they have already broken the profit margin.
also many operators use credit scores to determine what level of contract they can offer that suits you then usually you get your new phone all pretty in its nice new box that was just yesyerday sitting in the warehouse after being reconditioned, see the scams are there all the time you justr dont see them.
there are alot of phones out there that are reconditioned after being used by the elite class of contracts and they are then passed on down the line after upgrades. so its not that difficult really to work out how the risks outway the benefits and why so many phones are free and credit is available to all.