Taekkyon was supressed and there is no real reason to believe that it had anything to do with early TKD...
I have this theory about taekkyon, but mind you this is pure conjecture on my part.
Suppose that we as little children were told stories about King Arthur and the Knights of the Round Table, and when playing outside we turned sticks into swords and played at being knights, etc. Then some invaders came along and said, "You're not allowed to tell those stories or play like that any more. What you
can do is tell stories of
kenjutsu and play at kendo swords."
Then 35 years later, we're allowed to play however we want, and tell whatever stories we want. I suppose our children who grew up playing nothing but kendo would still play at kendo, but as adults we might try to recreate a tradition of what we remember from our youths about King Arthur and medieval knights. "Here kid, let me show you how Lancelot would have done it..."
Is it possible that when taekwondo pioneers returned from Japan with karate, but wanted to recreate a tradition of Korean martial arts, they turned to their childhood memories and said, "Well, there was this one thing called taekkyon that I saw as a child at festivals, and that my grandparents would tell me stories about...but it was mostly fancy kicking." Is it possible that that's why early pioneers opted to emphasize and expand upon the kicking aspects of karate more than anything else?
In other words, I'm not saying that there's a shred of taekkyon
technique in taekwondo, but maybe there's some taekkyon
inspiration in taekwondo?
Of course we'll never know what was going on inside the heads of the early taekwondo pioneers, so my conjecture is completely unprovable. But I wonder if maybe the people who claim a little bit of taekkyon heritage for taekwondo aren't
completely nuts.