Could SCOTUS Use King v Burwell to Toss ObamaCare Entirely?

Okay, I had a thought. I am not claiming that SCOTUS WILL use this logic, or even that they are considering it. I'm merely bringing up this thought as an intellectual exercise... if any lawyer-type would like to weigh in on this, they are more than welcome.

Here's the current situation.

In King v Burwell, plaintiffs claim that the plan language of the law only allows subsidies in an exchange established by a state, while the IRS has "interpreted" the law to allow them to offer subsidies in Federal exchanges, as well. The Federal Government responds that the plaintiff's argument is ludicrous and the IRS action is perfectly in keeping with both the text of the law and the intent of Congress.

During oral arguments, Justice Kennedy raised an interesting point. He said that while plaintiffs could well be correct about how the law was written, implementing the law that way could raise constitutional issues.

Let me say that from the standpoint of the dynamics of federalism, it does seem to me that there is something very powerful to the point that if your argument is accepted, the states are being told either create your own exchange, or we’ll send your insurance market into a death spiral. We’ll have people pay mandated taxes which will not get any credit… on the subsidies. The cost of insurance will be sky-high, but this is not coercion? It seems to me that under your argument, perhaps you will prevail in the plain words of the statute, there’s a serious constitutional problem if we adopt your argument.

In cases such as this, it is common for SCOTUS to allow the rule to stand, as the alternative would be to create a constitutionally invalid law.

However, I'm wondering if there is a third possibility... could SCOTUS use this to toss the law entirely?

Here are my thoughts. Let's assume that five justices think the plaintiffs are correct on the wording of the law, i.e. that the law doesn't allow subsidies to be offered by federally-run exchanges. Let's further assume that those same five justices agree that implementing the law as written would create an unconstitutional situation where states are coerced by the Federal government. Okay, what happens next?

The government would want SCOTUS to follow past precedent and allow the IRS rule to stand, i.e. allow subsidies to federally-run exchanges, even though the text of the law doesn't allow that. My problem is that this is a precedent that could easily be abused by Congress and the President. They could write and pass laws that establish unconstitutional programs, but then implement rules that "interpret" those laws even more broadly to eliminate the unconstitutional aspect, and trust the court to allow the rule under the King v Burwell precedent. This would be a bad precedent to set.

So I wonder... could SCOTUS conclude that the subsidy program as written is hopelessly broken to the point that Congress must address the issue, and invalidate the entire subsidy program? If they do so, could they take it one step further and rule that, since the subsidy program is critical to the proper functioning of insurance exchanges, the entire statute must be overturned?

The administration has argued from the beginning that subsidies are essential to the law as a whole... indeed, that is the very essence of this case, that without those subsidies the federal exchanges would never work properly, and would enter into a "death spiral" of rising prices. Given that, and given that five justices (hypothetically) acknowledge the plaintiffs are correct that the IRS rule violates the law, is it possible that they could toss the whole kit and kaboodle?

I do not view this as a likely outcome, it is merely a conjecture that intrigued me. I wonder what a lawyer might think of this possibility?