With the apparent demise of Shake – really nothing real now, as it seems to have been withdrawn from sale – Apple appears to be redirecting enquires to the Final Cut Studio 3 pages, suggesting that they consider Motion a substitute for Shake. I hope there’s something else coming (“Phenomenal” anyone?) because Motion is not a substitute.
Now, before I get into the reasons why they’re not interchangeable, let me say that it might make perfect business sense to drop Shake and not replace it. Shake, when Apple purchased it, had about 200 customers. That number has obviously grown dramatically but I’d be surprised if there were 10,000 true users: people who use Shake as the high-end compositing tool it was designed to be. It was also obvious that Shake, as it was, wasn’t going to be able to move forward in any serious way: no way to hook into GPU power or other such lush goodness.
Creating a replacement from scratch – all new, modern code – is an expensive operation. For a company like Apple, probably in the tens of millions of dollars to not only create the application but to test it internally (the Motion team, at time of launch, had as many QA people as software engineers), put the marketing plan into practice, run launch events, seminars, create training resources, etc. At Apple’s level, software is an expensive business.
The market for high end compositing software is small, and in the time Shake hasn’t been developed competitors have been significantly upgraded and taken market share from Shake. Maybe the decision was made to simply take what they could from Shake and roll it into Motion.
But Motion is not now, nor ever will be, a replacement for Shake. Motion is a great motion graphics tool with compositing capability. Shake is a compositing tool with some motion graphics capability. You see the problem.
Motion is an excellent motion graphics tool for video editors. It is designed to make it relatively easy for non-experts to create some fabulous looking motion graphics. Shake, OTOH, was for those individuals who were trying to track a head  shot against green screen onto a body while putting the whole body into a scene generated in 3D while adding other 3D characters.
This would be a nightmare to composite in Motion, because it’s not what Motion was designed for.
So, while it makes perfect sense to kill Shake – it was old and needed updating, and maybe updating doesn’t make economic or marketing sense – it doesn’t make sense to pretend that Motion is a suitable replacement.
I suspect that the original purchase of Shake was more for the marketing benefit of being associated with Tentpole movies rather than the income from software sales. Apple doesn’t need that so much anymore (and that’s a good thing).
I’d still like to see what the Nothing Real team would do recreating the application from the ground up with modern technologies, but I suspect Shake will never be anything real in the future.