“…absent an effective mandate…”
Can’t argue with that.
Recall why ACA had momentum. The recession was at its peak. Millions lost their jobs and health insurance. Getting private insurance for most was impossible. Premiums had gotten to ridiculous levels far exceeding inflation. And the practices of private insurance (and small business groups, too) were designed to cherry pick the insured pools. Dropped, delayed, denied and rescinded coverage was the norm.
If you had pre-existing conditions that were treated by your previous coverage you could not afford or even get coverage when jobless or even changing employment in some cases.
Ideology squelched truly effective mandates. So the young and healthy just stalled as long as they could. There were some waiting periods as I recall, but not enough.
The most effective mandate is a tax, payroll or self-employment. Which is what many countries do for universal single payer. And health insurance, as you have argued, should not be tied to employment. This is particularly true in our economy in which people change jobs more frequently than in the past. No longer is 40 years and a gold watch the norm.
Under a private insurance system, if there is no prohibition against pre-existing conditions, a person could not change companies should his go under, raise rates or have bad service and the insured had been treated for some medical problems.
And we also need to recall that ACA was at its core, an insurance subsidy plan, not true healthcare reform. Prices were still high for all aspects of healthcare from providers to pharmaceuticals. So premiums followed.
There are so many issues involved that it would require pages to even address them.