Most major developments have precursors that are often only recognized in hindsight, at least to their full extent. The ‘running quarterback’ has been a part of the game of football for a very long time in the era of the forward pass, and you could dig up the old names if you want.
But the reality is that we are only now in the era of the game in which it’s truly accepted as a valid aspiration rather than a handicap. Mobility is, of course, a benefit, but until recent years, for virtually everybody who played the position, the focus was always to put the ball in the air.