You don't have to use normal installs (I don't like the term "sideloading") if you don't want to, you are still free to use the more limited App Store if you insist.

Apart from that, if apps installed normally don't pass iOS security requirements, that means the iOS sandbox is flawed somehow?

The AppStore review process is what enforces you have a sensible sandbox, why would a sideloading App Store enforce those, they don’t care about platform security.

As for “don’t install it if I don’t want to” you mean don’t I stall any software that insists on sideloading.

That's how it works for websites, it's even more straightforward, your browser just runs the code as it's downloaded and I don't recall many issues with that. Maybe Apple should improve their security in their sandbox if it's not ready for normal installs?

Well then, don’t?

So when every game company starts shipping its unsandboxed games through its own half assed unsandboxed store I just don’t get to use them. That sounds an awful lot like the monopoly apple is supposed to have.