Actually, zero profit is guaranteed only if the market exhibits perfect competition or monopolistic competition. Those that are not (which the wireline busines

Actually, zero profit is guaranteed only if the market exhibits perfect competition or monopolistic competition. Those that are not (which the wireline business should be in, given its very high barrier to entry and low number of competitors) do not go to zero in the long run because of the market power they control and tacit collusion with other players in the market. The 'razor thin margin' likely exists not because of competition, but because of inefficiency in the way the business is run.