Yeah I love linux, but it's user experience , while light years ahead of what I used in the late nineties and early aughts, is still clunky compared to others.
That being said, honestly most of linux's issues are GUI related, when it comes to going mainstream. The capabilities and efficiency are far ahead of windows and mac os but most users don't care.
Directions, examples and mundane work should all be seamless for mainstream consumers.
A good rule of thumb is, " if a user has to look for it to fix it, or open a terminal window to install software, then it won't be accepted fully.
Mainstream users don't want to type commands in a prompt. Why does everyone think windows blew DOS out of the water in sales? It wasn't because DOS wasn't working. It was, hell early windows ( I started on 3.11 so that's my limit of knowledge ) still used DOS.
So bottom line. Start putting the non tech consumer first or we'll forever be stuck in this "almost mainstream" category forever.