Linux is a terrible main OS for anyone but true nerds (so like 2~3% worldwide).
Nah, it's just familiarity with Windows that make it a problem for mainstream users.
Nah, it's terrible because it is made by and for nerds, with nerds logic, ideological bias, and expectations, and of course the usual blinders and denial in regards to any non-nerd needs and criticism.
Like too many projects in the FOSS world are anyway, baseline MAME included.
Look up the "OS learning curve" meme : it is the truest thing ever about Linux period.
Linux's fine and its superpowers actually put to use when it is completely hidden and/or automated so any random end-user using it for a specific purpose doesn't have to actually know nor learn how to use it. Otherwise it is really not for normies, never was, never will.
In a way even if it's really far away from an actual Linux OS distro, Android is maybe the greatest Linux success ever, and people who use it were always just as familiar with Windows in case you didn't notice.
Why are they fine with it? because Windows and Android are both OSes designed with accessibility for normie end-users in mind, with
their reality and (non-)skilled needs.
Linux isn't. Not at all, all the distro efforts attempting more friendliness to normies have been failures.
Really, Linux as a desktop OS, for anyone but the small demographics of nerds who are mad enough to prefer a mountain of precise input commands lines in place of three mouse clicks, and don't miss all the cool software and hardware everyone even our kids and grandmas use, for anyone but them crazy nerds, Linux is useless ---steaming pile of meadow muffin---.
And it being free doesn't change anything at all, Windows and Android completely own Linux when it comes to free software anyway, and you can have them for peanuts these days.