As an aside, I love that this got downvoted here. Do people think most corporations are paying $11k+ each year for each employee for retirement benefits?

I would certainly not bet that they are, but if you imagine an employer that paid a reasonable amount in an ideal world, it could easily be that much. $11K is barely over half the 401k limit and health care for retirees is costly and not particularly visible so I at least have no idea how much that should add but it might be significant.

Two separate questions are - is $11K a reasonable cost in general, and is it reasonable for whatever the USPS actually needs to fund? I think it's obviously a reasonable cost for the sort of benefits that I personally would like, and for the sort of retirement most SWE HN participants expect to be able to fund. It could still be a vastly excessive amount for whatever USPS employees actually will get. The number really means nothing out of context.