100 episodes for syndication is an urban legend. The minimums are 13 and 65.
Shatner owns 5% of Star Trek? Never heard that, source please?
Inside Star Trek: The Real Story - Herb Solow and Robert Justman. And I think that was only for the network run, and/or limited syndication reruns. It's not like he still owns a piece of it.
If 100 episodes for syndication is an urban legend then a lot of studios believe it. This is why USA Network made a 4th season of Airwolf. While 100 episodes has proven to be a high number, and many shows under 100 episodes have lived on successfully in their syndie runs, 13 episodes seems ridiculously low. I can't imagine a series being cancelled halfway through its first season and everyone saying "well it'll at least be seen in syndication - it has enough episodes." They would burn through the inventory too quickly for it to be profitable. Even at one a week, when other shows were being stripped daily, by the end of the year, the whole series would be seen 4 times over.
Even a legendary show like The Prisoner, with its 17 episodes, didn't get rerun repeatedly.