[datavirtue]

Because their business is providing a solution that IT failed to. Despite the large cost, which the business was already accustomed to from previous IT attempts, pales in comparison to the additional costs of doing it themselves.

It's like the cloud in general, the cost is high but so is the hype. When all that dust settles over the coming years the business will start shopping on price. They will then realize they have been locked in to some extent and will need to start wriggling loose of the lock-in.