Those are popular provisions; they tend to make insurance coverage comprehensive but also somewhat costly. (The main reason that health insurance plans are expensive, of course, is because medical care is expensive, and the bill doesn’t do anything about that either.) Because they all stay, the rest of the policy changes are built atop a chassis of health insurance products that cost what today’s plans cost.

The bill effectively slashes subsidies that help many low-income people buy insurance, starting in 2020. A 60-year-old earning $20,000 in Lincoln, Neb., currently gets a subsidy of $18,470 to help her buy insurance, with extra subsidies to help her pay deductibles and co-payments, according to calculations made by Kaiser. Under the new legislation, she would get a subsidy of $4,000, and no help with cost sharing.

The bill also does away with Obamacare’s requirement that people have insurance or pay a fine. That provision is unpopular, but it is seen as an important incentive for healthy people to buy insurance every year. The Congressional Budget Office has estimated that eliminating that provision would lead to premiums that are 20 to 25 percent higher, even without any cuts in subsidies.

As a counterweight, the bill does some things that would tend to stabilize prices. It gives states a big pot of money to help keep markets working. It allows insurance companies to charge higher prices to old customers and less to younger ones. That is not so good for our hypothetical 60-year-old in Nebraska, but might help lure some healthy 20-year-olds into the market who don’t buy insurance now.

It also creates a new kind of financial incentive to buy insurance: People with a lapse in insurance coverage of more than a couple of months would have to pay a 30 percent higher price for their insurance when they re-enter the market. Advocates say this provision would get people to stay insured when they are healthy so they can afford coverage later. But some critics think it could backfire, since only sick people would be willing to pay the extra fee, which might not be enough to cover the extra cost of their care.

“The people who are going to take this gamble are going to be the healthiest,” said Craig Garthwaite, the director of the health program at Northwestern’s Kellogg School of Management. “The only time you are going to get them into the market is if they get sick.”