Who said anything about costs at the margin, i.e. 95th percentile? You've just 'moved the goalposts' across the field :) Bandwidth is a commodity like anythin

Who said anything about costs at the margin, i.e. 95th percentile? You've just 'moved the goalposts' across the field :) Bandwidth is a commodity like anything else and has underlying structural costs - it's far from free in any sense of the word. Even at the 95th percentile, as you say, there's no guarantee that there's unused bandwidth at all.