OK, hypothetical:
A software developer plans to release a very simple graphics program. He wants it to be able to do such things as Gaussian Blur, Hue adjust, Sepia, Distortion, Halftoning, and a little bit of needless things like Page Curls and Pointillise.
The developer, seeing a need to be compatible with the next version of the OS, finds himself looking at the CoreImage functions - lookit, he says - all of what I want to do can be offloaded to CoreImage!
Yesss
.
So he writes a three megabyte program (OK, that's a guess
) that, with the help of CoreImage, does everything he wants it to. It's not backward compatible with Panther, but he's not concerned about that. Tiger, he realises, will be the definitive OS X.
Tiger is released. He watches and weeps seeing how beautifully his little program works on his dual-G5. He gives it to his friend with an AlBook and it works fantastically. He couldn't be happier.
Then someone with an iBook gives it a go. Not only do they not get any of the effects, but they don't see ANYTHING happening. It's like every function does NOTHING. Same on the Mac Mini. Same (could be wrong here) on the iMac G5.
Word spreads that CoreImage isn't something you want to take advantage of in your programs - it's something that cuts out a huge chunk of the market; it doesn't SCALE.
Suddenly everyone has CoreImage installed in their OS and noone's taking advantage of it except Apple in the Dashboard.