The worst people in the world created schooling and the education system for their own narrow, selfish, greed and profit driven objectives. Is so deeply engrained, with the very “educators” themselves often not even realizing that through their having also done through the system, they are actually just enablers of an abusive and toxic, soul crushing system … which is precisely what it was designed for; because after all, “the purpose of a system is what it does”, and “ no point in claiming that the purpose of a system is to do what it constantly fails to do”; both the words of a great steward of systems thinking, Stanford Beer.
How big is that fraction? In my experience being around a bunch of home schoolers (and adjacent, and school system), some of whom were more in or out of unschooling, I think it's small enough that it should be a rarely considered option.
There are some kids where it will work _really_ well. I've interacted with a couple. There are a lot of kids where it really doesn't work, especially in a distraction rich environment.
If schooling and learning/education are truly mutually exclusive then who is the most learned and educated person you can point to that never stepped foot in a school? And how do those rare examples compare against the breadth of modern PHD holders?
There are a non-negligible fraction of kids that are kept out of school, homeschooled, etc. If school was as bad for learning as you suggest then one would expect those kept out of it to demonstrate higher-than-average aptitude.
It is also and equalizer. Unschooled kids from bad backgrounds now start even lower.