I never see bills from my employer based healthcare, and it's not anything super fancy, and it's not Kaiser, just BC/BS. I had a surgery that billed my insurance in the tens of thousands of dollars and I never saw a bill. My spouse sees bills but it's because she has her physician order tests that are a bit outside well established medicine that would never be covered by NHS in the UK or Health Canada.

My relatives on Medical never see bills.

It's not just Kaiser.