All of my research was before ACA so I don't know about the "new" ACA-compliant HSAs. Isn't "federal marketplace" an ACA thing?
I do know that in KC, Blue Cross Blue Shield was a big proponent of ObamaCare and when it was passed, they ended their old plans to push people onto ACA plans. The new premiums were typically around 125% to 150% higher in the first year than what existed before. These were small group/small employer plans. ACA did not FORCE them to terminate these plans - the company chose to. (I worked a short contract there - I saw some interesting stuff.)
Also in that year, people who had Golden Rule (UHC) plans called the company so many times that Golden Rule sent out a letter stating that they had no plans to cancel their grandfathered plans. I still have their PPO plan.
Maybe Missouri has some tight grip on insurance regulation but if they do that's about the only thing they have a tight grip on!
Everything else here seems very laid back and loosey-goosey.