" Many people believe the state should have never gotten into the "marriage" business in the first place."
You're joking, right?  Marriage is, at its root, a legal contract, mostly about conferring superseding rights to one person. 
They have first rights to your pension. They can't be forced to testify against you. They inherit your IRAs immediately, and get to treat them as their own since inception. There are no gift limits between spouses. Law defaults to them inheriting ALL your assets (unless otherwise specified).   Law defaults to them having the rights to your medical decisions if you're incapacitated.  (Before Oberkfell, the parents had hospital last rights over the long-time partner.)  Married couples adopt children jointly. (Before Oberkfell, only one could be the LEGAL parent.) It goes on and on. 
Anyone believing the state (i.e., the law) shouldn't be involved, doesn't understand the point.  Without the entire canon of marriage law, it'd be chaos.
"For instance preexisting conditions, you could get state coverage through Medicaid."
Only if you had no assets. Otherwise, you're in a high-risk pool.
Back the year before O-Care began, HRPs were charging $5000/mo, compared to a Cobra at that time costing ~$500-$600.
FTW, Cobra is usually equal to the highest-cost basic insurance for a 64yr old. Part of the reason is it's a catch-all, and part because it's more attractive to those who know they'll use it more.
MediCAID usually only kicks in when (almost) all other assets have been liquidated.