> we installed stuff on our devices

I am not sure about that. Windows, Linux based devices were like that but for a lot of things like gaming consoles etc. you were locked into the ecosystem and 'side loading" was indeed something.

I do understand developer mindset but I would be pretty unhappy if my mother's phone could just install stuff. A lot of people get harmed and lose their life's saving over wrongly installed crap.

A good middle ground for the Big Tech is to let folks pay $$, a money that is high enough and has sufficient friction.

That isn't even true about gaming consoles. They were completely open in the 90s and before. The consoles even lost lawsuits keeping it open. For newer consoles, a modchip doesn't side load, it enables normal loading without the drm check.

Bypassing/disabling drm would not be called sideloading.

If anything, the app store would be the sideload because they are loading the installer via a middleman instead of downloading the installer and running it yourself like normal.