The public option isn't supposed to be government supported. It's run by the government, but with a private budget, taking all their operating fees from users. A lot of people on the right are skeptical that it will become either de jure or de facto government supported, and comments like "I don't expect that many private insurers will continue to participate in the exchanges if they have to compete with a public option" are the reason.

I'm skeptical of that the public option will work as well as its proponents say it will. We already have non-profit health insurance companies, and they haven't completely eaten everyone else's lunch. But it's worth a shot, as long as it really truly sticks to that mandate of not being government supported. The argument would need to be really convincing given how many of its backers think it ought to be government supported any way.