Raw cloud computing costs have a fairly small margin over what they could be. Nobody with real purchasing power is paying anywhere near the listed retail rates. It's part of the reason smaller providers e.g. OVH, can remain quite competitive.

The other items have very strong lock-in and capture ecosytems. Microsoft Office is the first and only office suite anyone uses and its cheap enough for nobody to consider a real alternative. Microsoft could attempt to charge $10,000 a seat and while some will certainly stay, others would look for an alternative. But for just $10 a month, its a fair price to pay.