^TAS was syndicated here and there over the years. I definitely remember seeing it at various times after its network run ended.
I always thought it would've made sense to add TAS to the TOS syndication package -- add 11 pairs of episodes to the 79 TOS installments (since "The Cage" hadn't been released yet) and have a 90-hour package. If that had happened, maybe audiences would've been more accepting of TAS as an integral piece of the whole. But I guess a lot of viewers wouldn't have been as interested in an animated show. And since TAS was produced and part-owned by Filmation, the rights situation would probably have been different. Although that problem would've gone away once Filmation dissolved and Paramount acquired full ownership of TAS.