I find it funny how everybody here tries to spin this to portray Apple in a positive light, even putting the blame on Microsoft somehow. Face it, this would be a big deal for any other large company. When a tech giant builds his latest project on out-of-house infrastructure, how can this be good? At best, it is a waste of development resources (when it is temporary), At worst, it is a business risk/reliability nightm…
Every enterprise builds on infrastructure owned by others. That is what contracts are for. What matters is the degree of lock-in and who controls the roadmap. And the whole point of modern "cloud" infrastructure is that you don't own the hardware, you don't have the capital costs of the datacenters, you have a nice temporary lease that you can nonrenew or perhaps even break if needed, and your internal architecture is probably generic enough to be ported to another cloud if needed.