If you want to change an existing system, slice the salami thinly.
Whether they intend it or not they are optimizing for moving a lot of work overseas. They seem to think the economy is the same as in 1945. And even to get to 1945 the US imported a ton of nuclear physicists and other scientists.
No. I don't know if you're not familiar with what these terms mean, but by default most people don't have permission to work in the US. That's the default situation if there were no visas.
Visas didn't create this default situation - they're the tool that allows you to get permission beyond the default of not having permission.
If you had no visa system... nobody would have the needed permission. You're thinking everyone would get default permission but that's not the case.
No, that's not the point. If that's what you wanted to achieve then you'd be best off not having any visa system. So obviously this is not what they're optimising for.