Earlier quoted context omitted.
I think he should have written "disintermediated" for those examples. There are now fewer intermediaries, maybe only a single layer - but the companies in that layer occupy almost all of it. You can publish books without having to worry about publishing and distribution - if you go through the publication-and-distribution vertically integrated monolith.
I agree. Publishing overall is substantially easier. Publishing without going through the publishing monopoly is substantially harder though.
Generally for books and music the answer for "should I sell on Amazon, Apple, Barnes and Noble, Soundcloud, or my own website" is "yes".
In addition to convenience people are understandably leery about where they put their credit card info and the financial infastructure hasn't generally caught up although there are a few "one-off" credit card number generators.