'BobbyJo didn't say "no margins", they said "margins would tend toward zero". Believe it or not, that is, and always has been, the entire point of competition in a free market system. Competitive pressure pushes margins towards zero, which makes prices approach the actual costs of manufacturing/delivery, which is the main social benefit of the entire idea in the first place.
High margins are transient aberrations, indicative of a market that's either rapidly evolving, or having some external factors preventing competition. Persisting external barriers to competition tend to be eventually regulated away.
