This is another one that had been worrying me for a while, and there is some kind of answer in my read of the moment, Sushi and Beyond.
Apparently teppanyaki was specifically designed for the Americans staying in post-war Kobe and demanding meat. Not sure that is a full explanation though, as shabu shabu was also designed mainly for foreigners to begin with but never really took off outside Japan.
It could just be the name that has less recognition in Japan. The main dish in teppanyaki (at least in Japan) is steak and when the Japanese go for suteeki that is what they call it, however it is cooked.