You are assuming that the goal of all internet service providers
  is to have the best connectivity possible, without respect for
  cost, administrative overhead, or market strategy.

  If X is really really big, and Y is really really small, then
  perhaps it would benefit X to have Y as a paying customer instead
  of as a peer.

  The word peer implies equals, as it has so long been repeated.

  If provider X is missing 0.01% of the market share, and provider Y
  is missing 20% of the market share, who will be more upset, I