> but browsers only support the Flatpak stack

Well, I think you should blame Google and Mozilla for that.

KDE (through Discover, https://apps.kde.org/discover/) and GNOME (through Software, https://apps.gnome.org/Software/) both have innate support for Flatpak.

So, given that the majority of normie Linux users will use Flatpak to install a browser, they will just use and support that in the browser (because the underlying DE wil more than likely have Flatpak support integrated too) and go on with their day to day.

Means that people who don't want to deal with Flatpak have to deal with Flatpak (or at least parts of it) too unfortunately.

Most distros come with Firefox which most normies will simply use as is.

Also, software stores show both native and flatpak or on Ubuntu snap. One can easily install the system package of chrome if one doesn't want to deal with flatpak.