Microsoft has been playing with subscription-based models of their software for a while now, much like Office 365. From the looks of things. From the looks of it Microsoft could soon do the same with their OS, that would be Windows 10 in a subscription form,

Microsoft is headhunting a product manager for a consumer product called Microsoft 365, this is a software package that was only offered to companies. Microsoft 365 is a monthly subscription service that includes Windows 10 and the Office 365 package. Based on a job advertisement, it is now deduced that Microsoft will also target the subscription service, which is currently aimed at business customers, to end users. It is believed that the package will include Outlook Mobile, Microsoft To Do, and some MSN apps. 

The target audience would be huge and many users may even be happy to pay a monthly fee for a complete package of Windows 10, Office 365 and Mobility and Security. 

Microsoft might offer Windows 10 as a subscription