Politically, it makes some sense to try to avoid killing insurance companies altogether. That guarantees that they will pull out all the stops to try and kill the legislation.

On the other hand, when you start talking about mandatory enrollment with mandatory plans and benefits, now the insurance companies can run the actuarial numbers and sort out that they don't necessarily get killed. That's more-or-less how the Swiss system works. Insurance companies will happily sell you extras, above the mandatory minimums (e.g., would you like a private room the next time you're stuck in the hospital?).

I'd be perfectly happy if the U.S. ended up with Swiss-style healthcare. Much better than what we've got now.