Microsoft has a huge services and consulting division.
https://www.microsoft.com/en-us/msservices/?activetab=pivot1%3aprimaryr5
Contracts with large corporations and governments. Untouchable.
Did I mention that their value is closing on $2 Trillion? Bigger than the economy of most countries?
https://www.visualcapitalist.com/the-tech-giants-worth-compared-economies-countries/
Personal OS market. Hit them hard enough two things will happen. New PC manufactures will start offering Linux as a factory OS option, and MS stocks will take a huge hit. It will remind them that all the little guys are their bread and butter.