My family is happily using only Linux since 10 years, I since 15 years ago. But there are a lot of "but", without my support (I'm a sysadmin) they could not, but half of the issues are not Linux only, so they needed support even if they were using Windows. The real question should be "why even non technical users should use Linux?" You should not give a supercar to drive to a novice driver, it could be dangerous for him and for others. Every OS has its use, maybe I'm snob, but if you're not able to manage Linux rough edges use MacOS or Windows, Linux natural environment was and should be datacenter. I won't trade server features, robustness for having a Linux desktop at all cost.