Funny Ken, my old TKD teacher once said that at the beginning of the 20th century there were hardly any known Martial Artists who had the ability and know-how to kick head height.
I've read that Gigo Funakoshi, son of Gichin Funakoshi (founder of Shotokan) was widely credited with "nipponizing" his fathers karate by blending it with Kendo movements and adding in higher kicks. TKD was based on Shotokan, so perhaps that is where it stems from?? I don't know enough about it so all I can do is speculate. Shotokan Origins