I don't see a contradiction but a difference. You say: dismantling it would have other bad effects that would be worse than the direct bad effects of the monop

I don't see a contradiction but a difference. You say: dismantling it would have other bad effects that would be worse than the direct bad effects of the monopoly I wanted to clearly state that it's not some sort of abstract "other bad effects", it's that prices would increase for the consumer if the monopoly was disbanded. My thought/critique of ghaff's comment involves physical last-mile infrastructure. Alternatives to regular natural monopolies exist, but we'd have to have some pretty tight regulations on how, say, land beneath or above roadways could be used. The idea of having monopolies at local scales that compete at larger scales makes sense to me. But replicating last-mile infrastructure seems wasteful/bad/hard to solve (multiple companies building overhead power lines? multiple companies laying wire beneath roadways and apartment buildings? how do we deal with public land being used for private infrastructure purposes?) without some sort of regulatory control. Looking at it over sufficiently long time horizons and saying "well, it's all temporary anyway" kinda buries the purpose of even having a discussion.