How expensive is the cost of accepting insurance?

Time published an article about someone needing a knee replacement and ending up going to Surgery Center of Oklahoma for treatment. The patient shopped around and found that the surgery center that he ended up going to offered an all-inclusive cash price that was about half of what a local hospital quoted him.

Years ago, media had already noted how the surgery center is unusual in how it posts all-inclusive cash prices (in comparison to many other medical practices and hospitals where it can be a lot of work to find such pricing). What I haven't seen noted about the operation is that by requiring cash payments, the surgery center is able to offer low costs to patients while still making a profit by forgoing a large number of administrators. For years now, insurance companies have found ways of trying to save money. As time went on, doctors often allege that the rules to get paid became more and more complicated, requiring specialized office staff (which represent an additional expense). It would be interesting to know what fraction of a medical practice's expense is due to insurance requirements, and whether the industry as a whole could find significant savings by retooling the provider-payer relationship.