Might not? How about would not?
Meaning this case wasn't about an individual RKBA. If it was, the weapon would be immaterial.
It was important to the Supreme Court to know if the weapon was suitable to a militia. Why? Because if it was suitable, then the tax would be an infringement on the ability of a state to form a militia armed with those particular weapons.
If it wasn't suitable for a militia, then the state could form their militia without interference.
One last ditty. Who decides if the weapon is suitable? The Miller case was remanded because the suitability was in question. Think about it. Who is in the only position to make that determination?
Nice try, I know that is where you desperately want to get. Being a member of the "organized" or "unorganized" militia is only one of several reasons "the right (due to anyone by just claim, legal guarantees, moral principles) of the people (individual citizens) to keep (to hold or retain in one's possession) and bear (carry) arms (weapons, esp. firearms). Name a type of firearm that is not suited to the militia.