Linux is ALMOST there.
It's just the attention to detail that's missing.
Various programs not supporting Ctrl-Tab to move between tabs, etc, etc.
It's all in the details as Apple knows so well, and Apple's customers demand.
Perhaps someone like Xiaomi will invest in sorting out the details, just like Google did with Android, and make real Linux viable on the desktop.
EACH application installed must be made to conform to certain design criteria, or people will get pissed off, and rightfully so.
There are other issues, such as moving away from X11 one day. But those issues are not really any obstacle to end user acceptance.