A lot of people installed malware and, to be honest, nothing really happened. They might have had to change their passwords, but it could have been much much worse if Android didn't have good sandboxing.
I hope that Flatpak and similar technologies are adopted more widely on desktop computers. With such security technology existing, giving every application full access to the system is no longer appropriate.
You don't, but as far as I know, Flatpak or Snap are the only practical, low-effort ways to do it on standard distros. There's nothing stopping flatpak-like security from being combined with traditional package management and shared libraries. Perhaps we will see this in the future, but I don't see much activity in this area at the moment.
I hope that Flatpak and similar technologies are adopted more widely on desktop computers. With such security technology existing, giving every application full access to the system is no longer appropriate.