Microsoft is going to move everything to Win10, and eventually expire and stop supporting Win 7, 8, 8.1. Win10 upgrade is "free" if you don't count your time, bandwidth and frustration at finding where they've hidden everything this time
They haven't moved/changed anything as much as the average Ubuntu major version upgrade does. Yes, they'll stop supporting Windows 7 in 2020, and 8 in 2023. Reasonable enough.