Good article, but this is incorrect: “We also see information-delivery costs at zero.”
In order to take advantage of YouTube, WordPress, PDFs, and so on, you need a computer, internet access, and a good printer. That does cost something.
FWIW, my wife and I homeschool our kids.
Even if your kids are in public school, odds are that you'll still have a computer, internet access, and a good printer. He was referring to costs related to the retrieval of specific curriculum information.