Well, for starters, not everyone can buy private insurance. Insurance companies won’t insure those with high risk factors unless compelled to do so via group agreements. My wife isn’t able to purchase private insurance because she has two clotting disorders, Factor V Leiden and Prothombrin 20210 both of which are likely to have been misspelled here.
Even if that weren’t the case, I don’t know about the rest of you, but I wouldn’t even consider a job without health insurance, and I’m sure I’m far from alone.
Do you get auto and homeowner’s insurance from your employer too? No? Why not? Furthermore... why would you want to?
It's also worth noting that the Knights of Columbus was originally started as a life insurance company. Same concept . . . pool enough people together and the costs for those with the greatest needs are diminished.