Only 7% of Americans get their health insurance through non-group coverage, according to Kaiser [1]
It's not nearly enough to counter-balance to huge influx of high risk subscribers. You're being hung out to dry with the high risk pool, which is why your costs have skyrocketed.
"Most people are healthy most of the time, and as a consequence, health care expenditures are heavily concentrated in a small share of the population: about 50 percent of the health care spending in a given year by those below age 65 is attributable to just 5 percent of the nonelderly population. The lowest spending half of the population accounts for only about 3.5 percent of health care spending in a year." [2]
If you want to fix ACA, you have to fix the risk pool. So what's the best way to get healthy people signing up for ACA in droves?
Imagine if you could take your employer contribution, and legally apply it to any plan of your choosing. As-in, sure the employer could arrange a group plan for the office, and you could take it or leave it, but you got to apply the exact same employer-contributed dollars to any plan you chose if you wanted.
Then on top of that, if you could get ACA income-based subsidies, regardless of the amount of the employer cost-share. Because, why on earth should you get less subsidy at the exact same income level, just because you have an employer who is also good enough to contribute?! That's just penalizing employers for contributing. Employer contributions would be an add-back to MAGI for purpose of calculating the subsidy, but nothing more. Currently, today, the meagerest employee contribution will disqualify an employee from all subsidies altogether, almost regardless of income. So-called "affordable" employer-sponsored coverage disqualifies an employee from all subsidies, is defined as an employee share of less than ~10% of household income for an individual plan. WTF?!)
What you would end up with is some extremely cheap plans which a lot of very health workers would flock to. The Fed would pay out significantly more in overall subsidies, but the payment of subsidies would be significantly more fair because it would not penalize an employee for working for an employer who is actually willing to contribute to a share of health costs.
In practice, it would in quick order eviscerate the group market for employer-chosen plans, and see employees taking proper responsibility for choosing their own plans for themselves, while still preserving the ability for employers to share in health care costs with tax-advantaged dollars. It would save millions of small/medium sized businesses the arduous task of trying to negotiate group health plans for their employers evey single year. But most of all, it would fix the risk pool by getting everyone across America actually buying through the marketplace, and not the skewed microcosm we have now.
Early on after ACA passing, I think it was Zenefits was actually trying to sell employers on paying employees to purchased their own plans on ACA marketplaces years ago, until the IRS shut it down. But it was an extremely appealing model at the time.
[1] - http://kff.org/other/state-indicator/total-population/?curre...
[2] - http://healthaffairs.org/blog/2016/03/15/dont-let-the-talkin...