Re: the cost of all their services will be drastically reduced?
Not only that, there's also a concerted effort to impose planned obsolescence onto earlier versions of Windows.
It's one thing if Microsoft stops supporting and stops updating those older versions of Windows. It's another thing if third-party software vendors stop providing updates on older versions of Windows... and it has nothing to do with technological reasons. I'm convinced that Microsoft had somehow bribed, pressured or 'nudged' them to do so.
It's basically a mass genocide of Windows versions before Win10. Either Microsoft wants to force most users onto Win10 and achieve a critical mass of users so as to brag to shareholders, or Win10 'software as a service' (and the very interesting EULA changes) pave the way for a future subscription-based revenue stream.