Inertia. IPv4 still works, every service on the internet still available over it. You can just be lazy and things will be ok.

Complexity. IPv6 is complex in the areas where v4 sucks. Ran out of address space? Here’s a lot more address space. Multiple routers offering multiple routes? Just grab them all, have as many addresses as you want. No method to find peers on the same subnet? Here’s like three methods to find peers on the subnet. All this is stuff you gotta learn!

Workarounds. Initially, ISPs thought that people turned their PC off at night and they’d get the IP address back. Then, they were leaving multiple devices on all day! So they came up with a hack that pretends everyone is behind one IP address, now all your devices are just one IP. But that IP still stays up and occupied all the time, they’re not getting it back, so they put all their customers under another (CG)NAT. It’s just NAT all the way down whenever they run out, and this way they never run out.

You’re missing the point. It is “just” the act of downloading and installing, which were seen as normal things to do. However, by calling it “sideloading” they can then attach any meaning, any implication they wish. This is now something different and wierd, not something normal people do, does your mom sideload? I’m pretty sure the battle for control of your phone that you bought was lost as soon as we allowed them to call it sideloading.

I learned about these from the projectionist where I worked, back when I was a kid. When they’d get taken out of a projector and thrown in the garbage, he’d smash them on the ground to get the tungsten electrodes out. Apparently they both looked cool, like the surface of the moon, and sold for a lot!