The entire idea was using the threat of losing access to Medicare $$$ to force acceptance of all ACA plans by providers in order to drive down cost negotiations for individual payers.
Large companies get to leverage large group sizes, and the idea of the ACA was to effectively turn all government aligned plans including Medicare into a single giant "all or nothing" group.
But when the courts struck that down, instead it became the exact opposite, allowing for even more division and sub-grouping across ACA plans, which drives up the end payee costs because there's little to no consequences for providers telling ACA plans to get bent.
The ACA as designed was effectively a compromise, and then the courts reversing the key compromise meant the overall result was a hot pile of crap outside of finally ditching preexisting condition lock-in (which was still a win overall, but a much more minor one).
The only such parts I know of are the mandatory Medicaid expansion and some stuff related to covering contraception. (And the individual mandate penalty was reduced to zero by Congress in 2017.)
I was not aware of any part of the ACA that required insurers to carry certain plans, apart from the general regulations it introduced on health insurance plans in general.
It was even sold in a ridiculous way. “We all know health care is broken, so if we just force everyone to sign up, and give them more guaranteed income streams then it will fix itself!!”.
I don’t want to hear about how Obama actually wanted single payer or X. He knew exactly what it was the whole time.
“Medical billing” is an industry probably larger than medical care.
I fully support Costco here, insurance is a scam.