One complaint from insurers and outside technical experts is that the short development timetable, abbreviated by the tardy release of regulations spelling out precisely how the exchange should operate.

The exchange regulations were finished “way later than should have been tolerated,” said Gail Wilensky, a former director of Medicare and Medicaid under the first President Bush. “CMS and friends were making spec changes very late in the game and that really complicated the process beyond what it needed to be.”

Bob Laszewski, a health care consultant who works for insurers, said that the government’s own oversight report in June pointed out the missed deadlines and timetable problems.

“The GAO was being politically correct — it didn’t come out and say this thing is going to crash and burn, but if you go back and read it, it’s pretty obvious,” he said.

The report points out a number of delays at that point and major tasks still undone, including a significant share of the pre-launch testing, a rollout of the consumer assistance program, and the data sharing agreements among the agencies feeding the federal data hub that would spell out security protocols for all the sensitive information that the system would have to draw on to verify income, immigration status, and eligibility for subsidies.