I thought the Parker court addressed that -- they essentially said that it was wrong for the other courts to reject cases for lack of standing because that action pre-judged the outcome of the case!
If the U.S. Supreme Court is to determine either a collective right or an individual right, they certainly can't reject a plaintiff who is representing an individual right because of standing.
That IS what Parker said - which is decidedly in opposition to what a whole host of other courts in different Circuits have said. I don't have access to Westlaw, but I'd bet that hundreds of federal cases over the decades since Miller have said words to the effect of "We won't accept this case for failure to state a claim" - even though the claim stated was a violation of the 2nd Amendment-protected RKBA.
If the U.S. Supreme Court is to determine either a collective right or an individual right, they certainly can't reject a plaintiff who is representing an individual right because of standing.
That logic hasn't stopped other courts (see above). However, the Parker decision is an extremely well-reasoned position in favor of what you said here. For that reason, I think that there is a good chance of DC losing if it appeals an as yet hypothetical en banc loss.
I also believe that the mere existence of the Miller case (i.e. the fact that the USSC decided it on its merits, even if somewhat incorrectly) demonstrates conclusively that it is an individual right. Had the Court denied Cert. based on lack of standing, then the collective rights people might have a point. But it WAS heard on the merits - meaning that somewhere, somehow there IS an individual (i.e. actionable) RKBA. Miller didn't win because there was no record to establish that a short-barreled shotgun was suitable as a militia arm - and if he had an attorney representing him when the case went back down to the District Court, then that case would have turned out differently. IMHO, if you had a Miller-type case today with an M-16 or an M-4 at issue, you'd have reams and reams of evidence that would mitigate FOR protecting our right to own such weapons.