Great thoughts Steve. Yet another caveat to potential outsourcing. Having hosted various platforms for web hosting, I have experienced the sudden death of some existing features that was not expected.
I reckon this happens whether it is hosted local or outsourced, it just has more roll-back control when it is local, and more immediate response.
I remember the wild changes between PHP versions when they switched to the Zend engine... what a pain, especially with image handling functions.
Don't ever expect an outsource to do your homework for you. Systems and apps (whether outsourced or not) are still in-house responsibility, as the in-house bottom line depends on it. If not, then the in-house soon lands in the out-house.