Or better yet, bring back apprenticeship and give them something to do other than worthless high school. I almost didn't get my first programming job because I had to be paid under the table at 17 due to child labor laws. If you want to enrich teenagers' lives, offering them something other than a prison sentence where kids ruthlessly torment each other seems a decent way. It worked for most of history.
Each to their own. An apprenticeship wouldn't work for something like the sciences where you need to understand the theory before you can work under someone more senior. But you're right, for vocational training where you learn by doing having the option of an apprenticeship may be far more fruitful than staying in school. I believe Germany has this kind of system.
At the university, we actually had a very successful internship program for high school students (in particle physics). It turns out there is a lot you can learn by "learning by doing".
Also the actual day-to-day work of a master or PhD student is not too different from an apprentice in crafts - but very different from a school or univerity student. You learn by being embedded in a working group and performing actual work, instead of only sitting in class and learning from books.