"To increase coverage, you would have to see more states take up the Medicaid expansion, and some reforms to increase take-up in the individual (private) market," Katherine Hempstead of the Robert Wood Johnson Foundation told the Associated Press.

However, the Republican's American Health Care Act in its current form would limit Medicaid spending, likely causing more people to be uninsured, health economist Gail Wilensky told the AP. Wilensky, a Republican, is critical of the ACA and co-author of an alternative plan by GOP policy experts.

The AP says the stalled progress toward insuring people could also likely be due to the fact premiums for private insurance were about to "jump."

A Bloomberg article reports premiums for ACA plans will rise more than 20 percent on average in Maryland, Virginia and Connecticut — the first states to make filings public, according to data compiled by ACASignups.net and Bloomberg. The increases follow years of rising premiums under former President Barack Obama.

Last Wednesday, Aetna announced it would stop offering plans on the ACA exchanges in 2018.

"Our individual commercial products lost nearly $700 million between 2014 and 2016, and are projected to lose more than $200 million in 2017 despite a significant reduction in membership," an Aetna spokesman told The Daily Caller in an email.

Humana in February said it would pull out of the exchanges next year.

"We are again seeing signs of an unbalanced risk pool based on the results of the 2017 open enrollment period, therefore we've decided that we can't continue to offer this coverage in 2018," Humana's chief executive Bruce Broussard said in a conference call with investors at the time, CNN Money reports.