No other country works this way, yet they have college. So this argument doesn’t pass the smell test.
That opened up a flood of money to 18 year olds going to college, which in turn led to the colleges massively expanding their offerings.
Colleges in the US don't just educate. They are also the minor league sports programs for most sports in the US, and they provide luxury benefits like gyms and movie theaters and so on.
They can't go back now. They can't just stop doing all the sports with all the fancy equipment they bought, they can't just get rid of all the luxury housing and movie theaters and so on.
So yes, the US is pretty unique in this respect.
In any case not-in-DC it's more focussed on the BA segment of the population, but artificial gatekeepering is a thing (even in tech! I know many candidates that I wanted to hire but were turned down because they didn't have a BA in CS)
Most school districts have what’s known as a “step and lane” salary schedule for teachers. These grids specify how much raises are worth. Teachers earn a “step” increase for each additional year of experience, with many teachers peaking with the highest “step” at around age 55.
Teachers can also earn more by having more education (those are the “lane” increases). Some districts pay teachers holding a master’s or doctoral degree a premium, while others move teachers into a higher pay column when they earn a certain number of credit hours of professional development.