Healthcare - insurance costs

I am do for a divorce soon.  We were working on filing the papers when I hit a rough medical patch (stroke! tumor! an overabundance of intoxicatingly fun life happenings! I am being so sarcastic here...)  He did not finalize the divorce and leave me in the lurch, instead, he kept me on his insurance and waited.  As did I. 
We are gearing up the paperwork again, and I am taking care of medical stuff I was procrastinating on. 
My story is this.  I received the bill for the gall bladder surgery.  $38,561.00.  
                            My portion to pay.    $518.00
                             The amount they write off due to me having insurance?  $30,765.00. 

Let me get this right. 
If I did not have insurance, I would be on the hook for the whole amount.  Chances are I would not have insurance because I could not afford $600/mo (which is the cost of my specific insurance).  So I cannot afford insurance, but I receive bills that would eventually bankrupt me?  With my health issues, I won't ever go without insurance, but it seems ridiculous there is such a price difference.  It should be the same damn price for everyone. 
Oh, and, I have started asking how much visits and tests are... and frequently receive the answer ; Oh, don't worry, your insurance will pay it. 
I know they will pay, but since you charge a different price for me, and give me and my family more advanced and expensive tests because we have good insurance I would like to know what that is. 
And for the record, I am fully supportive of the affordable care act.