I don't agree. This has been said for over 20 years and it does not work out.
The change for IT costs for a large company to change from MS to Linux and all the automated processes, like SW installment, company software portals etc, outweigh the operational costs by a large number.
What I get from the IT guys is that MS is a company that gives good customer support when something fails. With an OS as Linux you have to wait till someone finds time to fix it or they won't because no-one else has a problem with it. The commercial Linux companies are too small to support thousands of large international operating companies.
MS is here to stay IMO, they goofed up with Win8 and the wrong way Steve Balmer thought it should go, but regained with Win10 which I find the best OS they ever made. Even the highest expecting users, the 24/7 gamers are positive, which is quite a difference from years back.
The only thing that could interfere IMO is if Apple were to ask decent prices for their computers. Instead of making them tiny, having only one socket (what idiot made that decision) , and priced in the ultra luxury Louis Vuiton and Prada pricerange while offering an obsolete slow performing POS, they could make a difference.