Any company that screws its clients without giving a damn is going to become unstuck at some point. Company A employess Company B to do something and Company B charges them 10x over the odds for this. They (Company A) find out at some point that this is going on and then they find someone else to do their work (IT in this case).

If anyone needs an example look at whats going on with (Linux|BSD|etc) and Microsoft. People see they get a raw deal and start to move away. It isnt instant and it can sometimes take the dumb ones several helpings of getting cheated before they realise but it will happen in time.