To support the statement that dumb pipes can be incredibly profitable: Intelsat. They openly admit they are a commodity business focused on MHz and Mbps, and have no problem consistently hitting 70% margins.
Consider Uber vs taxis - if there were massive entry costs to the cab / private car category, a company like Uber would have trouble raising enough money to get launched. So the existing cabs wouldn't ever experience the competitive pressure from Uber, because it would never enter the market.