That's certainly how it's set up today, but I find it difficult to believe that the most optimized, useful, and productive way to teach children about reality is the method we've settled on in the modern US. School could instead be designed around the production of art, goods, and services that are actually desired and used by people in and outside of the school. This would be a great deal more difficult to set up and maintain than a series of gradeable worksheets.
> Learning in school is about absorbing already existing knowledge.
Under the current model, is the knowledge really absorbed? Math class is great example. Most people struggle through algebra and trigonometry worksheets for a few hundred hours and then immediately dump the knowledge when they graduate and can't even name the three primary triangle side-ratios five years later. Was completing curated problem sets under threat of a worse career if they failed really the best use of their time? That can't be the best way to teach them.
> I spent a lot of time maintaining an internal inventory management app, which was eventually deprecated and now it's probably not used by anyone anywhere in the world, if not completely lost forever. Such is life. Still, I learned a lot from that.
Sure, but you were producing something of value. When you learned about an issue, you went hunting for the root cause because people were actually relying on you to do so, and when you fixed the issue you felt real satisfaction, and retained a desire to remember what you'd done. Also, you were paid.
I would wager a good deal of money that what you learned while managing the app stuck in your brain a lot more effectively than if the same activity had been taught to you in a class where you completed worksheets based on the inventory management platform.