I expect that the "losses" early on were due to those who were the most in need of some type of health insurance but were without it (notably those with "per-existing conditions" and/or inability to afford private insurance), and were thus "sicker". Fast-forward a few years and any whose health improved thanks to finally getting treatment, may no longer be in need of the most expensive care... but as the insurance model goes - they are still "paying into the system" regardless.

I.e., there was a heavy front-loading into the system of those in ill health, but for the long term, that number would be expected to drop.

Which is why Republican efforts to repeal Essential Health Benefits must be resisted.

https://www.theatlantic.com/politics/archive/2017/03/the-trouble-with-killing-obamacares-essential-health-benefits/520680/

The changes sought by the conservative House Freedom Caucus attempt to lower the price of insurance premiums by revoking the ACA’s requirement that insurers cover an array of 10 “essential health benefits”—spanning maternity care, mental health, and drug abuse, to hospitalization and outpatient care.

Critics argue such mandates inflate the cost of insurance by requiring consumers to purchase more insurance than they want: The classic example is an older male forced to purchase coverage that includes maternity care.

The problem is that if coverage of needs such as maternity care or mental health is not included in all policies, the only people likely to buy it a la carte are those who expect to use it. And that will rapidly raise the cost of such coverage—if insurers offer it at all.

“The losers would generally be people who want to buy a comprehensive insurance policy,” said Sabrina Corlette, a research professor at the Center on Health Insurance Reforms at Georgetown University. “Because once you give carriers flexibility to design the benefit package, they will do so to attract healthy people. No chump insurance company is going to be out there offering a comprehensive package, because then they'll be stuck with higher-risk enrollees.”

I will preface by saying that I benefit from Obamacare - my spouse and I were without insurance for several years until the ACA kicked in. We are relatively healthy. The subsidies are significant. It has worked for us so far.

However.... part of the reason the insurance companies are getting closer to profitability is because the premiums are still rising at a crazy rate. Each year, we've had to pick a lower-tier plan to keep our share of the premium affordable. This also means that our deductibles, copays and co-insurance costs have gone up. If we actually had a major medical issue the deductible and out-of-pocket maximums would kick our asses.

The ACA is helping a lot of people, and it is literally saving some lives. But for many people who at least nominally have insurance now, the actual CARE is still unaffordable if they need more than an annual wellness exam.

The insurance companies have to be cut out. In the long run, it is the only way to get genuinely affordable and accessible health CARE.

claiming that they were losing money but in fact the real reason they pulled out was as a ploy to get a proposed merger approved.

every dollar they make in profit is someone being denied needed care.