I'm a prof who has worked in both the US and Japanese education systems (Japan longer). As such, I've thought a lot about this.
The problem with your idea is right there in your last line, even though you didn't mean it to be:
Not everyone will become or even wants to be an astronaut and are perfectly happy as a mechanic or something.
The implication is that the former is a "higher" profession than the latter. Now, it is much harder to be qualified for, and therefore worth more money, but there's nothing low about being "a mechanic or something." In fact, if you find a good mechanic--someone who is good at understanding highly complex systems and who has the experience necessary to quickly diagnose problems in those dizzyingly complex systems--you pay through the nose for him, and are happy to do it. He probably still doesn't make that much, though.
This is because we have something wrong with our (US) culture. We don't seem to understand the concept of middle class. We don't seem to understand that the vast majority of people are basically as smart as everyone else, regardless of education level. We also don't want to pay for basic services, so those people have to compete for cheaper and cheaper prices. It also means that we get what we pay for.
I had a German hair stylist in the US for awhile. I loved her to death. She wasn't much for "chairside manners" (she was curt and pushy, without meaning to offend), but she was unbelievable. She could make anyone's hair do anything, and got most of her clientele through her ability to look at totally perm-or-color-ravaged hair, and fix it. I started asking how she did it. She said, "American stylists are terrible. They study for 6 months and wonder why they can't do anything right. I have a four-year degree." "A four-year degree to cut hair?" "Yes, but also coloring. We have to study organic chemistry for that and pass tests on diagnosing problems and coming up with solutions on different kinds of hair. The races have different hair, you see. What I'd use on an Asian wouldn't be what I used on you, for example."
Germany made a choice that vocations were still really important. And they are. But we don't see that in the US.
Japan is not as hardcore about this as Germany, but it still trains people much longer for vocations than we do in the US. Prices are higher, but so is quality, and so is the mode standard of living. I don't mind paying more to have my car fixed if I know that that guy's kids can go to college if they want, because he's very comfortably in middle class.
Our over-emphasis on the individual in the US hurts us in many, many ways. We idolize the rich and blame poor individuals for not working hard enough or something. We impose a moral hierarchy on the socioeconomic structure, and it is killing us. A large middle class means political and economic stability, lower crime, higher standard of living, longer lifespan... Everything great about Japan, I think, is due to their commitment to taking care of and respecting everyone (of course there are exceptions--nowhere is perfect). In a very real sense, the US's obsession with superstars, captains of industry, and themselves as individuals, I think, is the reason that We Can't Have Nice Things.