The point where insurers switch sides is going to be the crisis point. If OCare can’t come up with a way to buy them off in whatever system follows OCare, they’ll torpedo it. The “single payer” will either be an insurance company, or there won’t be one.
BTW, everyone cites England as "single payer," but they aren't. England has private health insurance. A friend of mine was treated over there under her husband's company's private plans. They are quite expensive.