Money quote right here: "Time wasted on learning what all the other 4 year olds know is time that can't be spent learning what they actually want to learning that will make them a unique member of society", you sir, are absolutely right. +1
That may be what you're saying, but I think the difference is important enough to be more explicit.
the question of whether they want to learn is roughly irrelevant here
the question is more, should their learning mirror every other kids learning?
the basic stuff, (reading, writing, numerical literacy) is so basically useful that'll it will be learned in context of exploring nearly any facit of life
I'd argue that encouraging your kids to explore their universe is vastly better education, than worrying about any paticular skill set in any paticular time frame
skill sets are almost always easier to obtain in context, as needed