The reality is that we do want to run code developed and compiled and delivered by entities we don't fully trust and who don't want to provide us the code or the ability to compile it ourselves. And we also want to run code that can dynamically generate other code while it's doing so - e.g. JIT compilers, embedded scripting languages, javascript in browsers, etc.

Removing these checks from the hardware is possible only if you can do without it 100% of the time; if you can trust that 99% of the binaries executed, that's not enough, you still need this 'enforced sandboxing' functionality.