https://www.bloomberg.com/view/articles/2017-03-06/selling-health-insurance-across-state-lines-won-t-save-money
"One reason is that it is already allowed –- and yet basically doesn’t happen. States possess the authority to sanction sales across their borders, and to define the conditions for such sales. In addition to this generic state authority, Section 1333 of Obamacare authorizes “health care choice compacts” across states. As of last month, five states had passed legislation allowing insurance plans that cross state lines: Rhode Island, Wyoming, Georgia, Kentucky and Maine. Georgia's law has been in effect since 2011, yet no insurer has yet offered an out-of-state policy there -- or in any of the other four states. If this is the key to bringing costs down, why doesn't anyone want to do it?"