That day may never come. Unless a SAM system turns on its radar it's difficult to find. The U.S. has aircraft specially designed to bait these systems into activating and then destroying them. (I know you know this, so curious why not factored into your logic here).

It's the same for both sides. How risky is it to fly over X territory? The only way to find out is by doing it. I don't believe Russia is stupid here. They have lost some serious aircraft because they're a bit desperate to get momentum (which they have), which you've explained in other pieces.

For Ukraine it would be the same thing. They'd lose F-16s. Like the lost M1 Abrams, it will be bad PR.

Could the U.S. use its doctrine to create a no-fly zone? I believe yes...but...at huge cost both politically (China would be spooked) and in material.

I agree with you that the U.S./Ukraine is trying to destroy as many of these systems as possible for the reasons you explain. I have strong doubts it will be effective. But, I guess, one thing at a time ;)