You can't waste money on the scale of the US system by simply paying doctors too much. Rather, you need to hire entire departments of nonproductive people - eg billing and administration. When you zoom in, most of these positions look like a necessary function, but systematically they don't need to exist. Take for instance a "nurse navigator", whose entire job is to deal with insurance company rigmaroles - as a patient you're extremely thankful to have them, but their position is actually only necessary due to a corresponding insurance company department (that you're also paying for!) trying to deny you care.

The ultimate problem is this planned economy mandate of "full employment". It is in no individual's interest to declare that their own job is counterproductive, otherwise they'll starve. So they hang on performing in their own little niche, sucking resources out of the system so they personally can continue living a dignified life. We're stuck in a paperclip maximizer, and the healthcare industry is one of the best small-scale illustrations of this.