Minecraft.
Steam.
Heck, every video game ever.
Skype.
Microsoft Office. Made billions when people had to physically go to a store and get it.
Google Earth. Chrome itself.
IntelliJ, any developer tool.
Zoom. WebEx. Most video conf tools, actually.
Any pro tool whatsoever.
You get the picture. No, ticking a box and tapping is not the end of the world and never has been. The UX for app installation on macOS and Windows is totally atrocious in both cases and people figure it out.
If you live in the Valley bubble world where every single app that exists is VC funded and desperately racing to get to a 100M daily actives first, then it might seem like one extra click is literally the end of the world. But FFS the vast majority of all businesses and products require more effort to get than that, and they work just fine.
But even if 99% of people could figure it out, it'd still be an unnecessary hurdle whose only purpose is to provide Google with an unfair competitive advantage.
Until all of that bs goes away, side-loading and secondary app stores will be nothing more than a hobby for enthusiasts.