SCOTUS will decide this on commerce clause grounds unless they can find some way weasel out of that and decide the case on some narrower grounds. What is worrisome is that prior precedent (Wickard, Raisch) probably gives them cause to rule the individual mandate IS constitutional.
Bad decisions make for bad law. We would all be much better off if Wickard had not been decided the way it was. Thomas is the only justice on SCOTUS that has the balls to say he will disregard prior bad decisions and instead to the plain reading of the constitution. The other justices will, I think, decide that the individual mandate is simply a bridge too far because it renders the commerce clause moot and expands federal power to everything. You might like "free healthcare", but you won't like the completely unrestrained federal government that will be unleashed by the final destruction of the commerce clause.