In addition to Office their Windows volume licensing is quite expensive, and I assume most of the Fortune 500 companies use Windows desktop clients. Sure they'

In addition to Office their Windows volume licensing is quite expensive, and I assume most of the Fortune 500 companies use Windows desktop clients. Sure they're declining on the server-side, but the majority of mid-large sized companies except for tech startups use Windows OS. For the companies who are 100% Microsoft and who happen to drift everything themself, it quickly gets ridiculously expensive if you calculate MSSQL, Sharepoint licenses etc.