Public schools are not as good as they could be, but that doesn't mean that the only option, or even the best option, is to homeschool everyone.
If our public school system were abondoned, then what? I think that people who couldn't homeschool would be forced to form some kind of cooperative. It would be run by some administration, and the leadership would have to do what it thought was best for the community, hopefully at the direction of the community.
...Which is basically what we have today, with the public school system. Except that in the co-op case it would be fractured, with each one teaching with its own bent. Sure, you could establish some global standard, but again, doesn't that just lead back to what we have today?
I think we should be grateful that we have options; take the one that's best for us; and support those that we think will be good for others -- realizing that it might not necessarily be the same as what is good for us!