'The discussion is about whether Windows will go away for ever after 2025. Some are claiming this is what MS have said. I disagree!"
You are correct. The last date for currently announced support will be in 2025 HOWEVER Microsoft can easily decide to extend that date just as they did many times for Windows XP. For all we know now Windows 10 could be supported into the next century.
Regardless of when Microsoft finally ends Windows 10 Support I believe, have no way of knowing for sure, that there will be a new OS available before 2025. However that OS might not be consumer oriented so Windows 10 will be around a while. Again that is just a guess.
Rob - SpiritX