If Windows 10 is the last version of Windows, why does its support have an end date?
I wonder whether there's still going to be a gotcha with regard to Win10 and support time frames, what with the "supported lifetime of the device" that MS mentioned and never fully explained.
The other odd thing about Win10 having a support date of 2025 is that for every other version of Windows, if you weren't running the latest "service pack", you don't get the full 10 years of support. The information in the OP is incorrect in that Win8 RTM is already out of its support phase as of Jan 2016:
https://support.microsoft.com/en-us/lifecycle/search?alpha=windows 8
So logically if you are still running Win10 RTM, you won't get many more patches (1.5 years' worth?), and certainly not until 2025, and yet if you're running the latest release of Win10, that date does not apparently apply.
So coming back to the current latest version of Win10 and support time frames, considering that Microsoft has trying a lot harder to rake in revenue in recent years (for example, there no longer being a 3-PC Office Home & Student version any more, and the rental version is nowhere near as good value for up to three users, at least not in the UK), I think it's illogical to assume that MS has decided to do its users a massive favour by allowing them to buy what are essentially non-expiring Windows licences (ie. the retail version of Win10); every previous version of Windows essentially "expires" due to support time frames and impracticality of running an older version of Windows on newer hardware. Not so seemingly with Windows 10 (unless MS decides to draw some new hardware compatibility lines for fun and profit).