This is just... Absolute nonsense. Just factually incorrect. Middlemen, example Amazon, have never been stronger. People complain about it on HN all the time.
Anyways, people use middlemen and are happy to pay the cost because they provide a useful service. They aren't just arbitrarily injecting themselves into transactions.
The strength of a middleman can be directly measured by how much they mark up prices. Does amazon really mark up prices more than the brick and mortar retailers it replaced?
Anyway, I don't think "markup" is very much related to how strong they are. I define "strong" as "how critical for business that service is."
I'm just using Amazon as an example, one that everyone can understand has a massive amount of power.
I think of distributors, not retail stores, to be pretty much the strongest middlemen there is. If you're making a widget are you going to hire someone full time to market your product to individual stores and then hire and maintain a fleet to deliver them? Fuck no you aren't, you're going to call a distributor.