There is still that unequivocal statement from a VP of MS that people that get W10 now will never pay for it.
A few possibilities:
1. As soon as you switch too much hardware, your machine is no longer licensed for the 'free' copy. So you'd keep your 'free' Windows for a year or two, then be forced into subscriptions.
2. 'New, better, faster, more secure!' Windows 11 will be released in a few months, and Windows 10 will no longer be supported.
3. Maybe they're lying.
The funny part is that the one Windows machine I'd actually upgrade to Windows 10--our ancient XP machine that we pretty much only use for iTunes--is the only one that doesn't bug us to upgrade.