Once of the things Ballmer mentioned back when we called Linux a cancer was the idea of software rental. It took 15 years before this idea really became better received by the market.
This has been seen with Adobe who now asks for subscriptions for their software. Microsoft has now been selling subscriptions for Office 365. Autodesk has started to also offer monthly subscriptions.
The main motivation for the subscription model is the provide cash slow to maintain a team of developers.
Microsoft, Amazon and Google have been far more successful with virtual machine in large scale data centers where users can websites or anything else they want.
Microsoft has bit its tongue and no longer considers open source to be such a threat. They realize open source has its place and Microsoft has recently spent vast amounts of money to modernize Linux to make it more suitable for data center use.
Azure has several distributions of Linux available and they have suggested that over time they may expand the selection.