> Each employee almost certainly saw the amount the employer was contributing when they selected their insurance plan

I've never seen that happen, ever, in 25+ years of being in the working world in the US. Not saying it never happens, but I've not seen it, and after asking around, no one I know has seen that info.

For what it's worth, my employer does make a bit of a production about how much they pay for our insurance. They make us all look at a document that gives a figure that includes our salary and benefits, plus a breakdown. I guess the point is to make us more appreciative in the face of rising costs? That said, I don't remember the amounts being clear at the time I chose a plan, though maybe they were.