These cost increases are just the result of the removal of subsidies through ACA etc. i dont think thats really the problem. Its devastating to many, but the real pain is yet to come. And that will come from the cessation of thousands of public health services that were once provided.
These services were probably the biggest subsidy that any private companies have ever received. A person - or family has their premium calculated against a set of tables. These tables evaluate various risks, with probably the majority focussing on the odds of exposure. It might calculate your chances of being hit by a bus, but it is far more focussed on what are the odds of you getting on a bus with someone who has TB. Or buying your lunch at a deli where an employee has hepatitis. Or the odds that your kids go to a school where some of the kids catch measles, or mumps or whatever.
You have a government that is closing down vaccination clinics and discouraging their use. They have removed the rights of school and workplaces to demand their students/ staff have vaccines - when the inevitable hits, they will no doubt be unable to demand masking too.
When there are outbreaks, the offices which once monitored for them will be gone, and so will be the measures they may have put in place to contain the spread. The government have taken away both the preventive measures and the measures once there as a back up plan. And with no measures to control or report, a city or state might be headed into a disaster that nobody is reporting on.
Insurance companies base their premiums on factors like this. With every safeguard removed, they will not only have to pay out for more sick insured customers, they wont know that an epidemic is even under way or how bad it may get. When the extent of a crisis is unknown, an insurer is going to err on the side of caution and base their premiums on worst case scenarios.
This is just the initial stage of the problem. Since hospitals can find themselves sometimes having to treat the uninsured, they will try and recover those costs elsewhere. They will increase prices and add charges. The reason emergency rooms tend to charge an immediate bed or emergency suite fee of $1500 or so has nothing to do with the cost of treating you. Its to recover the lost revenue from treating the uninsured. As hospitals up their charges and the average cost of a visit increases, not only will hospitals start closing down, but insurance companies will have to factor in another reason to increase their premiums.
I suspect there will be many, many millions who were just about managing to pay their premiums without help from ACA. The required increases in premiums will leave them unable to pay