You might be right. Or it may be a combination of the two. Regardless of the reason, it's going to be from economic hardship due to idiotic policies. I'm not getting into the political realm of this, but when gas prices skyrocket, even 15-20 mpg cars won't cut it when you can buy cars with 40 mpg +. So when people stop paying stupid money for the "regular" GN's, 442s, Monte SSs, etc., G-bodies and such, so too will the demand for the mantle piece versions that sit in the corner sucking up spare money thrown away just to keep it looking like it would go fast.
And then again, pragmatically, what's so special about the GNX anymore? Historically, for those who lived it back then, it has more significance in my opinion, because most of the younger crowd look at you and go "whut?" at the mere mention of the cars of yesteryear. 13-14 second cars aren't all that and a bag of chips today. 276 or 300 HP or whatever they actually made back then was something, today your turbo 4 cylinder in the Ford Focus RS can keep up all day long with just about anyone behind the wheel. Similar 0-60 and 1/4 mile times and 350 HP for the Ford. Who needs a V6? And that's before any mods. For less than 1/2 the price or lower, you can purchase plenty of cars of today that could make a GNX look like a pig in every aspect of performance. But that's not what makes it collectible. It's the dream of kids who couldn't afford one then can afford one now. Even if it is almost 1/4 million dollars. And with less than 600 made, that's built in rarity.
As I stated before, I'm NOT afraid of a GNX blowing my doors off because it's straight line performance is middling by today's standards, and the ones that are left likely will never leave their parked positions except on a trailer, and not flogged if they did drive one down the road. I doubt I'll ever see one on the street again in regular traffic. So I ain't scared. I still think they're cool AF, but that's because I lived through those days.
In other words, the groups that actually care about a GNX is getting smaller. I'm glad they made their stamp on the world, but I think it would have been nicer to start off the G-body performance cars with engineering they used on the GNX.