i have quite a bit stocked up, but yeah i'd imagine that the type 100s (669, etc.) and 600 will be fairly available at least up to two years after it is discontinued, mostly on ebay, for close to normal prices. you figure there are probably tens of thousands of packs out there right now, mostly just being stored. like the guy i bought the case of uv id film from who has 48 cases (50 packs a case) of the stuff and prices it to sell.
i like expired film, so i'm not too concerned about 5+ year old 669 and 667 (667 seems to still work after 20+ years in my experience). i think the oldest 600 i've had that wasn't fully dried up was 12 years old...around '96. the big stuff will be the toughest to find. already less of it and less market saturation. those that want it, keep, it. plus it's the first to go according to the site.
10 years from now, who knows. i figure the peelapart will be dirt cheap because it's not the popular film (and there are already alternatives), and 600 will be like time zero, with people spending $35-$40 a pack.