Art in my mind the public option is the final safety net where the various pools have failed to achieve their intended effect, since nothing's perfect. I think having it as a department within Medicare and run by DHHS is a perfect location for it. It's eligibility would tailored to the still-underseved populations, maybe states that aren't running their programs up to standard, or, if employment based insurance still lives, it will be a backstop for people who still get screwed by that system. It's Medicare-For-All-Who-Need-It. The only people in it are people who would be VERY glad for its availability (without their having to be unemployed AND destitute and selling the family house or farm) and a very popular program with people wishing they could get into it. If they end up there because of bad behavior by insurers then government recovery specialists go after the insurer, instead of a sick person in financial crisis who has almost no rights anyway under emploer-provided insurance.

Wyden-Bennet is (deliberately?) vague on that subject and that's laregely where negotiations and debate need to take place.