They really can’t. Windows personal versions are what makes it attractive as corporate desktops, which brings in a lot of money and favors their brand of lock in. Every Fortune 1000 has thousands upon thousands of VDIs, each with its own Office and Outlook connected to either a huge network of Exchange servers or a hosted SharePoint+OneDrive+Exchange environment, all brought together by an Active Directory.
Take Windows out and the whole rest of the proposal gets less attractive.