I also think it’s worth looking at the states where things are going well and the insurers are making money: California, Vermont, Washington. Those state exchanges made some different regulatory choices early on that got more people into the new markets right away, so their markets stabilized more quickly.

Reed: You’re right that you may not need the established players for the market to work. The market may not look the way we thought it would, with the same insurers and same characteristics as the employer market. But one of the reasons insurers are leaving is because of the market’s instability. There’s tremendous churn in this market, with most people switching plans every year to try to find a cheaper alternative.

I’m not sure I know what the business model is for an insurer, if the expectation is that you’re going to keep your customers for only a year. It makes achieving long-term goals like keeping people healthier and focusing on preventive measures much harder because there may be no payoff for the insurer.

Margot: Yes, I think this is one of the contradictions of the Affordable Care Act’s design. The whole idea was that competition between the insurance companies would help to hold down prices, the way it does for, say, electronics or groceries. In order for that system to work, you need people to actually switch plans if their plan starts charging more than the competition. The fact that people are actually switching seems like a sign that this market is functioning as it was designed. But as you point out, all that churn sure makes it hard for an insurer to make money by investing in its customers’ long-term health. But the individual market, pre-Obamacare, also had a lot of churn.

Reed: Yes, there’s always been churn, but the insurers got pretty good at figuring out which people they wanted to insure by turning away the people who were most likely to cost them the most money. They definitely figured out how to make money.

It’s easier to smooth all of this out if you insure more people. Do you think there’s opportunity to see the market increase in size? I know insurers in the early years suffered when some states allowed people to keep their existing plans. Those plans that were grandmothered, as it is called.

Margot: My sense from talking to folks in the industry is that the grandmothered plans really wrecked their early calculations. The Obama administration, responding to a political freakout about people whose plans were getting canceled in 2014, let states keep them for a few more years. The result was that healthy people tended to hold onto their old, cheaper plans, while sick people went to the exchanges. You can see how that might make the exchange market unprofitable for new entrants.