That’s better than a system where future janitors are still expected to grind math problems instead of having a childhood

What? I went to an American public high school, there were/are plenty of kids who are very smart. 8% of my graduating class were in the uber-advanced honors math track. This is in a flyover state outside a small city.

I also used to work in science, the reason there's so few chances to make it as a top researcher is that there is little opportunity. Look at jobs for a lot of life science majors after a BS, you will find a ton that is washing glassware in a lab, a complete waste of anyone with half a brain.

There's reasons why there is little opportunity that's not worth exploring here, but suffice to say there are a ton of very smart kids in America that choose other paths. Outside tech and specialized physicians, nerd careers are not lucrative on average. With little opportunity, smart people end up doing banal work. Why do banal work and have a mediocre salary predicated on jumping through higher than average academic hoops? Doesn't add up for most people.

The original question was about what value educated people can bring to the economy. You are asking about most people.

And I reject your characterization of the capabilities of American students. There are plenty of incredibly bright ones.

Yes, and what you’re describing is inaccurate. This is a meme promulgated by the for-profit education industry but it’s based on people not comparing like cohorts. The American education system is huge and includes everyone, so if you compare averages it appears to produce worse results than systems which track poor/lower-performing kids out into vocational education, exclude kids with special needs or limited English proficiency, etc. but if you compare matching cohorts based on socio-economic status, etc. the results aren’t bad. The trick is realizing that research over the last century has shown that the most accurate predictor for educational outcomes is the socio-economic stability of their parents at birth, and the United States has both a lot of poor people and done less to help them than many of our peer countries.

Regarding science, there are plenty of American scientists who graduated from public high schools. The problem there is that even highly-qualified students probably aren’t going to have a research career because the funding isn’t there to support it - even if you look at people who completed graduate school that was like 1/10 even before the Republicans’ savage cuts.