There are at least 37 Bazillion Speed King pedals floating around out there. Don't worry. It'll be at least three, or four decades before Speed Kings even start to become 'a rare commodity.'Bill Fulton is sitting pretty though! He owns a bunch of SK's.
Yes, I'd say you should be just as worried that Avedis Zildjian has quit making 1960s and 1970s cymbals. They stopped making them in 1980 and there are still 37 bazillion of them around used, and used prices haven't shown a sharp rise (have they shown any rise?). And that's more than three decades after Avedis quit producing them.
I'd expect a similar pattern.