“Slower” implies you’re projecting the same end results. Do they think the missing numbers are just not using a computer at all? In the digital age? By far your largest numbers of actual Win11 migrators are companies whose tech policy is the CYA “update everything in case we get hacked”.

The common folk are not going to buy a new computer just to get a slower Windows installation. The people who migrate from Windows 10/7 holdouts are going to be migrating to Linux.