I'll start by saying I agree with the premise of the article - transparency of pricing is not just helpful, it is necessary.

However...I can also understand why paying by cash should much cheaper Adding another company or companies into the transaction, trying to standardize the various medical procedures, invoicing and managing co-pays, deductibles etc adds a significant amount of overhead.

One would hope that the insurance companies would leverage the volume of transactions and the pools of clients to get price improvements but this is not the case.