100,000 is pretty decent by US-released Japanese RPG standards. Off the top of my head, I know Radiata Stories sold 120,000 in total overseas (non-Japan) sales (so less yet for the US), and that game isn't remotely considered rare. In fact, it has a rarity of 1 in the Digital Press guide, which is as common as the scale gets, and we can assume The Last Story would get a 1 or 2 too with its similar sales. Plus, this is not even getting into the fact that there was a second print run, which I would guess is probably not less than 50,000. When all is said and done, The Last Story is probably going to be more common than most US-released Japanese RPGs. I mean, we already know it's more common than every single other RPG in XSEED's catalog, so I'd be more inclined to pick some other well-loved title in their library as something that would likely go up in value down the road.

I don't put a lot of weight into initial hype-spurred spikes in value. Games like The World Ends With You, Etrian Odyssey, Shin Megami Tensei: Nocturne, Disgaea, Katamari Damacy, Final Fantasy Tactics, etc. etc. were all selling for more than their full MSRP not that long after their releases because the initial demand was surpassing their availability. Then after reprints (some of which some people never saw coming [and were crushed and angered when their expensive game lost value]) or the interest simply waning as the games got older, the values dropped.

I am accounting for demand, which is why I'm saying they could possibly pull in $20, which is about the average price for PS1 RPGs that are well-liked, but I think expecting them to have high values later on is a bit much. Sure, it's theoretically possible, just like how Final Fantasy VII went for a lot despite boatloads of copies being out there, but just assuming that they're going to be impossible to find and really expensive when the signs aren't really there borders on fear-mongering. It's like with the old adage about how Atlus games supposedly always become rare/valuable, which convinced many gamers/collectors to snatch up all their games at the full MSRP, despite that many of their games, RPGs included, have seen heavy markdowns and are still extremely cheap and common. But as long as gamers are kept scared, thinking they'll have to pay out the nose later on, they'll keep dropping full price on game after game. In fact, it might be fear to blame for Xenoblade selling above MSRP right now. These people may be rushing to buy and paying extra because everybody is convincing them that it'll be even more expensive later.