It's actually about whether or not it would cost more, over the long term, for a company to develop such capabilities themselves, or to outsource it.
Generally, due to economies of scale, a big, established provider will be able to provide such a service much cheaper than it would cost you to run an equivalent service.
However, it depends on how much that provider is charging you, on top of their cost of sales. It's pretty basic in that if it costs more to do it yourself, it's easier to let someone else do it. Especially when you take into account the considerable R&D costs that it would take to provide an equivalent service. Google's services would, I'm sure, be highly developed. This statement says as much, in that it claims Google has services offered by no other company.
So no, it's not arbitrary.