no automatic updates
Well it’s really not entirely true unless you’re on a rolling release (which most people should if they can do basic system administration themselves). Unattended updates were a thing in traditional Linux distros with frozen release cycles since forever. On any Ubuntu-based system it’s a matter of switching a toggle, and I think it could’ve been Mint that enabled that by default (I’m not sure) at least for security updates, because users never updated their systems. They can still be done much quicker and more transparently than Windows does that, without ever forcing users to reboot in any given time.
The problem is also that once in like 5 years you absolutely have to upgrade system to a newer version to keep it updates in such scenario. Popping up a dialog with info that your system goes EOL and you’ll loose security updates and one click upgrade button should be enough.
There’s absolutely zero reason to expect Linux mass adoption as it is NOT happening anytime soon. What can happen instead is increased market share to something like 10% and even that is super optimistic from a long time user perspective.
The focus should mainly go to relatively technical users that can at least manage basic stuff and not mass market consumers. It’s good when people try Linux, yes, but it’s even better when they find it useful, it does what they need and they keep using it, not just trying and go back to a primarily supported OS that’s maybe invasive but “at least it works”.