Shake and Motion are two very distinct beasts, and Motion was hardly a replacement for Shake. But that’s not the point.
The point is whether Apple wants to maintain and grow market share in the professional venue.
From Apple’s actions EOL of Shake, Color, Server, DVDSP, CinemaTools, the removal of FCS3 for sale at the launch of XFCP, and now, the comments of someone who was on the inside of Apple’s decision-making process, it appears the answer is NO.