The problem is that most normal people (HN is not normal - mostly for the better) don't even understand what sideloading is - let alone actually care.
How can we fix this?
(aside from making people care - apathy enables so many political problems in the current age, but it's such a huge problem that this definitely isn't going to be the impetus to fix it)
turn people onto sideloaded apps. show them Revanced and NewPipe, show them system-wide ad blockers and bloatware removal and every other thing Google doesn't want plebs to use.
people don't care about "apk side-loading," they care about apps. hook them on forbidden apps, and they'll raise hell when they can't side-load them anymore.