That's a nice economic theory you've concocted, but it seems like you're living in a bubble. The reality on the ground in the US is that college degree inflation happened every bit as much in the EU by a generation of middle-class people who saw a college education at the ticket to prosperity. Now to get any kind of decent job requires a college degree. Federal loans are handed out like candy, and people snap them up despite not having any financial basis for that decision. Because the loans are unforgivable in bankruptcy, there is much lower risk in handing them out. Because the loans are easy to get, college tuition rises higher and higher outside the realm of real market forces.

The fantasy that the US system is someone leveraging market forces to optimize efficiency is ludicrous. 18-year-old kids have no idea of the impact of 5 or 6 figure loans at various interest rates and their expected ROI. Even many of their parents, who had good post-war working class union jobs with a nice pension and affordable homes they could buy in their early 20s have a blind spot around this because all they know is that the career paths they enjoyed are dead and gone and just some vague ideal that "college-educated" is still a meaningful adjective.

Frankly, it's an embarrassment to even try to sell the idea that the US system is better. The only significant difference in outcomes is that a huge portion of young Americans are destroying their lives with unmanageable debt, where EU citizens may get an inflated degree but they won't be an indentured servant for the rest of their lives.