Many of the government-run marketplaces were overwhelmed by visitors since the start.
But the persistent lags and difficulties getting through the enrollment process on Healthcare.gov—which is acting as an insurance marketplace for the 36 states not running their own exchanges—have drawn the most attention.
"What was supposed to be 'simple as buying airline tickets on a website' has turned into trying to find a needle in a haystack," said Barry Sloane, CEO of Newtek, a health insurance brokerage for small businesses.
The Health and Human Services Department, which operates the federal marketplace, is working aggressively to fix the site's slow speed, which it blames on too many people trying to create accounts, and check out the prices of plans being offered by competing insurers.
But experts have pointed to software flaws as the main source of problems.
(Read more: Obamacare deadlines)
Sumit Nijhawan, CEO of insurance data integrity provider Infogix, said, "My crystal ball tells me it's going to take anywhere from six to nine months" to resolve those problems. Nijhawan said the problems could get a bit worse before they get better when exchanges start dealing with a large influx of people enrolling before the Dec. 15 deadline for the start of coverage on Jan. 1.
More strains to come
Joel Ario, who headed HHS's health insurance exchange office from 2010 until 2012, told Time.com that government exchanges need to quickly make necessary tech fixes or face serious enrollment problems.
"By November—certainly the middle of November—the sites have to be able to handle major traffic for people to be able to set up accounts and purchase coverage," Ario told Time.
Infogix's chief product officer, Bobby Koritala, said many of the strains will come after people are enrolled and have their eligibility for government subsidies to buy insurance verified.
"The membership subsidies are simple" to handle, Koritala said. Much trickier, he said, will be processing billings, changes in people's incomes and calculating the subsidies that can be used to offset the cost of out-of-pocket expenses such as co-pays.