I think the vast majority of people use a PC for only basic functionality, like browsing the web and editing documents/spreadsheets, and for these users, Linux works fine. My 70yr old mum is a classic example of this - she used all versions of Windows from 3.1 to 7, and she switched to Linux about a decade ago and has zero issues. If my mum can use Linux, so can the average Joe.

It's the power users, or users who've got specific proprietary software/hardware requirements that usually run into issues: gamers who play games with kernel-level anti-cheat, professionals who're dependent on Adobe/AutoCAD etc.