>> the risk in the public ACA pool is lower than the employer's pool of employees
as a general rule, the public pool is substandard rating.
That's a weird way of putting it. Young people are getting far less value from their healthcare premiums than the old. That's how the entire system is able to work.
Health insurance, social security, medicare etc. all discriminate against the young in favor of the old. And I'm not passing judgement for or against such a system. That's just how it is.
The ACA is actually a wealth transfer from the young to the old, like social security, because the young pay much more than their portion of healthcare costs, while the old have a ceiling on their healthcare costs.
Whether this is good policy is for the think tanks and politicians, but after the ACA it is not true that health insurance discriminates against older Americans.
Medicare exists only for the elderly.