No doubt, there are several hucksters flogging inventions for the sole purpose of luring gullible investors. But many enterprises fail, without deliberate deception, owing to inadequate marketing or business model.

Fact is, only about 1-2% of inventions produce meaningful profit. The rest may serve as foundations for further development by others, or nothing at all.

The rolling loop was a major improvement. Aside from optical wizardry (octagonal prism), it's the only way to move very large chunks of film. The IMAX format is about 65mm wide, and runs sideways. With 4:3 aspect ratio, each frame is about 90mm long, and at least 3 frames (including the neighboring frames) must move effectively 48 times per second (24 in motion, and 24 stationary). Because of inertia, conventional claw pull-down would shred the sprocket holes instantly. High speed (for slow-motion photography) is even worse.

Cheers,
Joe