Well this depends how you see it. Since ill-health is a certainty, not buying insurance can be viewed as engaging in risk conduct affecting financial burdens that extend across state lines. This will be the government argument and it has the support of Gonzales v. Raich. The concurring opinion of Justice Scalia is worth a read.
I would point out that in Raich the Court essentially said that regulating the “intra-state” market of marijuana was essential(hence, why the N&P Clause could be used to effectuate the regulation of commerce here) to the regulation of the “inter-state” market. Here, to my knowledge, there is no “inter-state” health insurance market. Health insurance cannot be sold across state lines. So I would distinguish Raich in that way.
I would also argue that in all of the prior commerce clause cases there had to be economic activity that was the subject of the regulation. In Lopez, Congress attempted to regulate gun possession and the Court found it to not be a proper use of the Commerce Clause because the activity was non-economic. Here, I would argue that existing as a citizen is non-economic.
In none of the prior cases was a citizen compelled to purchase something. So none of the cases are exactly on point. It is one thing to regulate EXISTING intra-state marijuana markets as necessary and proper to effectively regulate the inter-state marijuana market. It is another thing to COMPEL someone to purchase INTRA-STATE health insurance in order to regulate INTRA-STATE health insurance markets.
I do realize that the left will argue that health insurance affects inter-state commerce due to its effect on all kinds of things related to health (supplies, etc.), but I think the fact that there is actually no commerce taking place until the government compels it to take place is a very strong argument in our favor. Again, in all other cases “commerce” was already taking place whereas here it is not until compulsion of commerce.