Right, but the root of the problem is that secondary education in the US is abysmally bad in many places, so a diploma from a US high school is mostly worthless

Right, but the root of the problem is that secondary education in the US is abysmally bad in many places, so a diploma from a US high school is mostly worthless. Requiring additional catch-up education is just a band-aid, and now with that being watered down, employers will want to see graduate degrees. That's even more money, and more time: employees will be almost 30 by the time they're ready to work. The solution is to fix secondary education, but there's no political will to do that.