I think that Microsoft is trying to set itself up for long-term survival. If I knew what they should do to succeed, I would be richer than Bill Gates.
I speculate that a lot of their motivation involves fear rather than greed. Microsoft has been around long enough to see the changes in computing that have lead to the rise and fall of whole market segments (like minicomputers). MS had a major scare over 20 years ago: I'm pretty sure that the Web wasn't part of their business plan in 1991.
Most of the desks that I've sat at over the past 20 years have had black boxes from Dell on them. (Some of my neighbor's desks have had laptops in docking stations, but I've avoided that.) I wouldn't bet a nickel that will still hold in 2035.