If you'd asked around at the Constitutional Convention the Founders would be unanimous that rules that they were writing would never allow the government to force someone into a business transaction. Then again, they'd be equally firm that growing plants on your own property for your own consumption would also never be the Federal government's affair. So there's a fair chance the Supreme Court will allow it to stand. It's going to be interesting seeing what future uses get made of that power. Will a future Congress fine me if I replace my car with a Ford instead of a GM product? The government has a direct interest in GM's sales now after all. I haven't come up with any ideas for what the other side will do with that power yet but I'm sure there's Republican legislators thinking of some truly horrifying possibilities for when it's their turn again.
Part of why I'm so distrustful of the HCR legislation is that it's so excessive compared to their supposed goals. Covering people with pre-existing conditions doesn't require a two thousand page law. Just declare that being denied insurance on those grounds makes you eligible for Medicaid. That might fit in one page even with definitions.
The "job lock-in" problem isn't solved by this either. There's still a huge tax penalty for not getting health insurance through an employer. If grocery stores other than the one at work had a 50% sales tax, I'd be buying my groceries at work. And bitching about the quality, because this outfit has no special competency at procuring groceries. No more than it does with health insurance. Now instead of my insurer having its top goal being making a corporate accountant happy they want to keep government bureaucrats happy. This is not likely to make them more responsive to what I want.
HCR is making it even harder for people to avoid that mess. Catastrophic-care only policies are being outlawed (so much for the promise that anyone who likes their insurance will be able to keep it). Choosing to only pay out of pocket instead of having insurance is also illegal. You can't buy directly from a company, you'll have to go through an "exchange" which will prohibit policies not meeting a long list of politically popular rules. Even using flexible spending accounts is being restricted to a $2500/year maximum. That's going to be rough on homebirthers. It's also going to eliminate an incentive for people to plan major surgeries instead of waiting for a crisis. None of these restrictions were necessary for taking care of people with pre-existing conditions.
It's probably the unintended consequences of all this that will be the worst. Innovation in medical technology is going to be restricted by the centralized decision-making. The best progress we've had in the past half-century has been in the most decentralized fields. Centralizing control of medicine is going to slow improvements a lot.
There's also a slippery slope problem. Once you're paying for your neighbor's health care you've got a vested interest in how he takes care of himself. There's already a provision in the law mandating calorie counts on restaurant menus. Outlawing the unhealthiest foods follows logically. The bottom of the slope is Winston Smith in 1984, getting hectored for not doing his calisthenics properly in his own home.