Honestly I think it is a matter of the scope of the case. This isn't a constitutional carry case or a concealed carry case or cutting at the NFA or GCA. This case is about NYC saying "fine you can own it, but you can't take it anywhere except these few places and only if you get prior permission...
I thought they did back in Heller? They ignored tiers of scrutiny in the majority opinion and went with the Historical Context review. It was Breyer in the dissent that created the 2A-two-step the lower courts have been using. But for whatever reason (Kennedy & Roberts) the Court hasn't taken...
A majority of the court may not be for defending/expanding 2A rights, but they don't appreciate lower courts pulling a fast one on them. NJ did it with Drake and as a result, I'd expect them to be very hesitant with any future slight of hand from lower courts/elected officials.
SBRs & SBSs were put in the NFA b/c the writers of the NFA also had handguns on there originally. They were trying to outright ban as many firearms types as possible.
VA was also shamed into fixing things by the mental health issues related to the Virginia Tech shooter. The General Assembly got it's act together and made changes to the laws that closed loopholes & fixed problems that allowed the Tech shooter to purchase his handguns
They're just following the pattern NJ set up with Drake, say "hold on we've got this other thing happening that could impact this case" and then once the SCOTUS acquiesces go back to business as usual and not follow through on what was used to stop SCOTUS.