I've been wondering about this for ages.
If you look at the card backs on the movie figures, it says 'CLASSIC STAR TREK' and there's an illustration of the original 1701; it looks very much as if designed for a general TOS line and the movies range is just a subseries. I also find it odd that each of the TOS gang in the bridge box set comes with accessories and a display stand.
Given that TOS characters only started appearing after Playmates created the consolidated Star Trek line, and that the bridge playset and, later, bridge station figures were cancelled, I wonder if the company got cold feet, perhaps had some doubts over the viability of TOS toys with 90's kids? I could be barking up totally the wrong tree.