Meh. I'm sure it's worse for non-Americans, but US border control is more of a hassle for me than any of Europe or China. Africa was pretty bad (they confiscated my passport...?) but otherwise the US is generally the worst.

The US charges $100 to sign up for Global Entry, while Australia is trying to force as many people as possible to use SmartGate with no fee and no registration required...

I travel internationally maybe 6 times a year and on average spend maybe 10 minutes waiting in line and 30 seconds talking to the officer at CBP without global entry.

I've timed it with friends with global entry going through at the same time and they shaved off maybe 5 minutes.

Either ATL, SEA, LAX, JFK, and MSP are way better than average, or global entry isn't worth it except for the tiny percentage of international travelers that commute that way.

Point being, for US citizens, CBP is plenty fast enough without global entry.

I have waited 2 hours at sfo just recently

And they don't really have to let you in the country.

American courts have ruled that it's unconstitutional to bar American citizens from entering America.

I don't think you understand the context of that decision. You do not have a right to enter the USA as a US citizen under all circumstances. You can be denied entry based on suspicious behavior and circumstances, and the border agents have plenty of free reign to interpret that as they will.

Would you care to provide links to cases or law that shows US citizens can be stopped by CBP for refusing to answer questions?