I know they do not get reimbursed the whole fee from the insurance company...they get paid the "agreed upon fee" (I think it's called) from the insurance company...and in some cases it's AMAZINGLY low.
I had a T who said he was only keeping my plan for me and a few others and that they were difficult to deal with and not really worth his time...I could see online what he was getting, and frankly, he was right (assuming he had billing issues with them as well like he said...I know I have had LOTS of issues with my plan).
Regardless, make sure you get all the time you should be getting while in there!