I agree with your points however it is difficult to imagine an alternative at scale. Small scale homeschooling may work but most do not have the ability to teach multiple subjects at multiple levels to their kids (and most don’t have the time). Additionally, society expects you to have been through the mainstream education system, so when applying for jobs etc you are expected to have standard qualifications. Experience is more important later in careers but initially you are expected to have a certain standard level of education!