Interesting link, and I think your disclaimer (mentioning SPEED RACER) is dead on. I think this is a list of films that had final deliverables prepared for 4k projection; I highly doubt that this many films were scanned and color corrected at 4k... especially titles like THE OTHER GUYS. Frankly, 2k is widely considered "good enough" for theatrical release, and is certainly the economic choice of studios.
However, even if every one of these listed titles (in the link) were actually scanned at 4k, then color corrected and output again at 4k, it is still only a tiny TINY fraction of the movies we watch on the big screen. It's the exception rather than the rule... although I'd love it if it became the rule.
So I guess my point goes back to the topic of this thread... the LOTR movies were shot on film with visual effects and color correction applied at the industry-standard 2k resolution, so the blu-ray image shouldn't have to suffer at all compared to most modern films we're used to seeing in HD.