I think, just like anything else, the value will vary depending on the seller and the buyer. As the old saying goes, beauty is in the eye of the beholder. And much of it depends on the quality of the ad.
For instance, a seller with a high customer rating, selling an SKS with high resolution photos, and many of them, and who knows what angles/nuances on which to focus, will undoubtedly get a far superior price than someone who looks like they took their photos with a 1MP camera circa 1998 and includes two photos.
Also, the ability of the seller to communicate authoritatively their knowledge base makes a HUGE difference.
Also, some sellers have absolutely no idea what specifically is of value to a buyer. And an informed buyer can sniff an uninformed seller. I don't know how many times I have seen the "not refurb" and "all matching" description on an SKS, and you see clear refurb marks on the dustcover or stock, ###ed out serial numbers on stock, and not even original stock. Those collectors know what year has what type of wood and what marks to look out for. If they run into an ad by a seller who is equally as informed, it will more than likely produce a higher sale value.
Some sellers will advertise a Tula 1954, but if you look at the stock, it's not even the right kind of wood and it's a single stamp of the serial number without the arsenal symbol and the year. But the seller can (knowingly or unknowingly) claim "all matching", though that doesn't mean "all original".
Some people will pay more money for an SKS that is all matching, irrespective of how it is matched, or irrespective of condition. Some folks are looking for specific features, specific years, etc. Some simply look for something decent that is local. The price tends to reflect all those factors or more.
I do think that the notoriety of the SKS has been amplified in some of the infamous tragedies have occurred when they have been used. And yes, the threat of gun bans certainly elevates the price. Look at how those Dr. Seuss books skyrocketed once bookstores indicated they will start banning them. It is human nature, to want the forbidden fruit, to an extent. I am sure many of the proposed C21, G46 listed firearms have been in high demand since it made it to the list, SKS included.
I do think that the prices have leveled out somewhat, with the big shipment of mint conditioned Chinese rifles that hit retailers last Fall. Those who simply want something in "new" condition certainly found that sale compelling. I am not into Chinese SKSes, but I did think more than once of dropping some funds on one just out of FOMO.
With the G46 amendment pulled, perhaps the rush to buy SKSes and as such, the premiums placed on some of them, may start to decline. But I also think there's a bit of a renaissance afoot insofar as historical military rifles go...and the fact that many of them are still in more than satisfactory operational fitness, would lend me to believe that there will still be strong demand for them going forward. From the collector's vantage point, time is not stopping and with the passage of time, surely the value of these old collectibles will continue to increase.