(This just to counteract my overly weighty response as sibling to this)
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...
Pre-ACA a non-group plan that wasn't some government mandated high risk pool would typically be much cheaper than group coverage, simply because of the fact that it went through underwriting and you could be denied.
It was priced similar to life insurance where a healthy young subscriber could get a very cheap premium because the expected value was so low.
Back when it was legal to charge 10x more for a 55yr olds plan than a 25yr old, people paid more in line with their expected utilization. Flattening the rate curve shifted massive costs to young middle class families, which IMO is shit policy. When you're 55 you are generally done raising the kids and saving for their college, so it's actually not a bad time for your health care premiums to skyrocket.
Now think about who is buying ACA plans off the marketplace. First, it's almost entirely people eligible for subsidies (86%) since the plans are cost prohibitive without them. Second, it's people who didn't previously have or couldn't get insurance, unemployed, or who aren't offered insurance through work.
You can see immediately the problem... ACA subscribers will overwhelmingly be high-cost subscribers. There aren't any healthy subscribers to ACA because healthy Americans are working and get their insurance through their employer and therefore aren't eligible for subsidies and have no reason to look at the high-cost exchanges.
The ACA is effectively cornering the market for super-high risk pool, and premiums on ACA markets will continue to rise to reflect it.
If the subsidies were available regardless of availability of a so-called "affordable" employer sponsored plan, and if they employer's contribution could be taken by an employee and applied to an ACA plan in addition to subsidies, it would fix this all in an instant. Suddenly healthy Americans would be shopping on the exchanges, fundamentally altering the risk pool and drive down premiums for everyone.