Microsoft's monopolies are extremely profitable and give than advantages into new markets (eg, retailing). They hope to be able to also leverage FOSS on their terms (pushing technology, standards, organizations, licenses, etc, that they control, lead in, patent, or are heavily invested it) to help them beat out Linux and other threats to their monopolies.
They want to tap into the time and efforts of volunteers (this much hasn't changed).
They can't eliminate what attracts people to FOSS, but they hope to set the terms of the game so that dollars and control flow towards them and their closed monopoly environment.
Monopolies implies monopoly pricing and control. Losing existing monopolies (all else that is material remaining mostly the same) implies stock price tanking and losing levers and openings into new revenue streams.
Hopefully, SCOTUS will make a decision on software patents that helps society and is consistent with the US Constitution. Neuter software patents.
Hopefully, those that value FOSS will see through Microsoft's games and work on real FOSS instead of contributing in ways that augment the value of Microsoft's monopolies.
The question I have is, when is Microsoft going to get serious and open source their platform and applications (and drop sw patent attacks) instead of polluting FOSS?