There are ways of squaring the circle. There are user experiences that can make even the dumbest user understand that they are taking the security of their device into their own hands.
Once they understand that, it isn’t up to Apple to decide for them that the iPhone that the user purchased must remain secure. Users must be permitted to make potentially dangerous choices with their own hardware if they so choose.
Mac users can disable system integrity protection and modify the OS or run unsigned apps (though the hoops to do this get more burdensome each OS release, and unsigned apps can’t use the secure enclave, or modern VPN apis, etc - another scumbag move by Apple) and the sky hasn’t fallen over there, nor in Europe where sideloading on iOS is mandated by law (and Apple implemented).