Hospitals aren't charging insurance companies $30 for Tylenol and then paying insurance companies under the table if that's what you're alleging.

That's completely illegal and it's just too noticeable for them to do it large scale.

The OP was making a baseless claim because they didn't know what they were talking about, and you're now grasping at straws supporting their claim for some reason.

None of the stakeholders in American for-profit healthcare have any incentive to reduce costs so everything just keeps ratcheting up. Growth can't be achieved by increasing the population of sick people so the only other option is to raise prices. The insurance companies do benefit from this. They agree to cover the inflated pricing so that their 20% cut can be bigger. If ACA permitted rational price controls this whole problem would have been reigned in.

How does this have anything to do with

>I think they're just pocketing the difference between the market rate and what their costs are.

The OP had made a very specific claim about Kaiser. That Kaiser is reducing their costs but pocketing the savings and not passing them on to consumers.

I pointed out that there is no legal way for them to do that. You've made 3 posts and so far nothing you've said in anyway refutes that.