Insurance? Or continued cost?

I try to keep political banter off my site. It's annoying, it's pointless, and all it really accomplishes is making the target public official - and the one speaking out against said official - look like a total ass.

Nevertheless, I received a bill from the dentist today, in the amount of $50. Funny thing is, I have dental insurance. And even funnier, I recall talking to the receptionist at the dentist's office about what I owe.

Here's a breakdown:
I am provided dental services which total to $980.
My insurance company says they will pay $700 of this amount.
I pay $280 to the dentist, and am on my way.

If you were following along, it's very simple math. Add the insurance amount of $700 to my payment of $280, and you come up with $980. Which is the total cost of the service.

Fast forward to now, where I am staring at a bill for $50. One of three things has happened here:
One, the dentist misquoted what my insurance would pay. That'd be fine, except I would check what insurance companies pay before telling the patient.
Two, the dentist undercharged me. Instead of services totalling $980, they really meant to charge me $1,030. Oops.
Three, the dentist got paid $700 from insurance, $280 from me, and decided they wanted more. So they hit me with $50.

I'm not sure what to make of this. I don't know of many products or services that explicitly state "You owe me this much." then later send you a bill saying "Whoops, we actually want more money."

Upon talking to several people, including the dentist, about this strange phenomenon, it seems it's a well accepted strategy by healthcare practicioners. The strategy is follows:
Tell the patient services will cost (x), insurance pays (y), and your cost today is (z).
Bill insurance for their amount of (y), and collect your payment of (z).
Insurance comes back saying "Nope, we don't think your service is worth (x), we think it's worth (w). So we're only going to pay (v).
The healthcare practicioner accepts the new insurance payment of (v), which falls short of the original plan of (x). Since the new insurance payment of (v) as well as your payment of (z) no longer equal (x), you get stuck paying the difference (t).

Only in the healthcare world does this seem to make sense. I can't remember buying a gallon of milk from the store only to have the dairy send me an invoice stating the store undercharged me for the milk, and I'd have to come up with another thirty cents.

Before we talk about national healthcare, government-mandated healthcare offerings from businesses, or any other "buzzworthy" topic relating to such, let's fix our current healthcare practices.

Doctors know insurance companies are going to pay a lower percentage than advertised, so they jack up their prices. Insurance companies respond by paying even less. The patient is stuck with the difference.

Sadly, my opinion of healthcare is rather...skewed. Dump the insurance companies. Go one way or the other:
Healthcare is a government entity. Docs are paid by the government, the population gets free healthcare paid for by taxes.
Healthcare is for those who can afford it. If you get hit by a car crossing the street, you should have learned to look both ways first. If you get shot by a crackhead mugger, you should have taken a different way home.

I'm a bitter little shit sometimes.