Next year's price cuts help to correct the huge increases that jittery insurers set for 2018 plans to protect themselves from anticipated Republican assaults on the markets. (Photo: Getty)

In recent years, places such as Memphis and Phoenix had withered into health insurance wastelands as insurers fled and premiums skyrocketed in the insurance marketplaces set up by the Affordable Care Act. But today, as in many parts of the country, these two cities are experiencing something unprecedented: Premiums are sinking and choices are sprouting.

In the newly competitive market in Memphis, the cheapest midlevel “silver” plan for next year will cost $498 a month for a 40-year-old, a 17 percent decrease. Four insurers are selling policies in Phoenix, which then-presidential candidate Donald Trump highlighted in 2016 as proof of “the madness of Obamacare” as all but one insurer left the region.

Related: 7 things to know as ACA open enrollment kicks off