Actually one of the aspects of HIPAA *was* the guaranteed issue of policies without preexisting condition exclusions if you had 18 months of creditable coverage immediately preceding. ...
If you took a job which provided health insurance, that health insurance had to cover preexisting conditions if you had 18 months of creditable coverage immediately preceding.
If you then FIREd in theory the insurance company had to offer you a potentially very expensive individual policy, if they offered individual policies in your state. However, that part had multiple holes. My big Fortune 500 company paid United Healthcare to "administer" their "self insured" company health plan, which meant no guaranteed issue policy was available. I was also turned down by the only company which then issued individual policies in my state.
That left the state's federally mandated High Risk Pool which supposedly had to take people losing Cobra coverage. It did NOT have to take people losing individual coverage, and my understanding is that some states had extremely long waiting lists to get into their High Risk Pools.
In the individual market, if you had creditable coverage and changed HI plans, the new plan had to cover your preexisting condition. However, no insurance company had to agree to take you as a customer. Basically, if you could show you never used insurance, you could buy cheap insurance. If you disclosed that you had been using your insurance, you probably wouldn't be offered insurance at any price. If you didn't disclose all your health issues the insurance company could retroactively revoke your insurance.
Which is why I waited to FIRE until the Supreme Court declared the PPACA was constitutional, and my COBRA coverage could bridge me to the first health exchange open enrollment period.