I guess it kind of depends. Not really sure what most people actually use, but for those who use MS's services, Office web isn't great, and Skype for Linux is rather temperamental. A lot of games work under Proton, but not all.

My perception of "average user" is probably skewed towards being not technical enough to troubleshoot on their own, but skilled enough to run through a tutorial of what keys to press. For someone used to Windows, patching things up is simpler than learning all the ins and outs of a new OS.

I don't disagree that most people would be fine using Linux, but there needs to be a compelling reason why Linux would be significantly better, or else the switching cost makes it not worthwhile.