Professors across the country (three West coast, two east coast, one sw) have told me that undergrad is going to shit actually, but grad school is still ok for now.

Shitty high-school means unprepared undergrad students, which means comparatively better foreign students.

More honest professors admit that it's universities that are really dropping the ball.

Do they blame the professors or the administration?

If it's the professors all hope is lost, since future professors will be taught by the people who are currently dropping the ball.

And yet, more and more of the students at the top schools are international. The non-top schools are failing to provide students with competitive schools, but are still driving students into debt.

We may have quality teaching, but we are not educating ourselves.

Maybe international students are at the top because you guys have terrible high-schools.

It's also possible that the reason the top Universities are at the top is that the top foreign students want to go there. That means giving Americans more preferential treatment may "break the spell" so to speak.

No argument here—high schools are part of the problem. Even more of a reason to invest there now rather than over seas.