These stats can't be fully trusted because they're mostly based on guesswork, but clearly, one piece of guesswork here is way more off than the other.
We know Windows 10 passed 1 Billion users in March 2020 and if the Netmarketshare/Statcounter stats are to be believed, Windows 7 has about a quarter of Windows 10's users, which would mean over 250 Million installs. If Ed Bott is to be believed, those percentages are off by double digits and the Windows 7 share should be more like 7%.
I can fully see why so many still use Windows 7, it was a stable OS that worked and didn't try to be a jack of all trades, like Windows 10 does.