I think more realistically I think you mean, "thanks natural market effect where even among competing entities there's strong pressure to charge very close to customer's willingness to pay since undercutting your competition risks a race to the bottom where all competitors suffer."
Why aren't other markets like that? Lots of firms in lots of industries have single-digit margins over COGS. They're at "the bottom" all the time. In some industries, defectors from the commercial collusion you describe are punished through non-market means. In telecom, FCC prevents them from existing in the first place.
