Huh? Could you explain this? So how did the jujutsu masters of the past, that had remarkable skills before the advent of aikido, do this this then? Did they not have the "secret" yet?
I think you have it backwards, actually - the jujutsu masters of the past DID have it - they just didn't call it aiki.
Aiki isn't something O Sensei or Sokaku Takeda invented, it was present in slightly different forms in many different arts. O Sensei's gift to us - and kind of a loaded gift, to be sure - was to create an art that took what was deep, inner, secret stuff in the ancestor arts, and plunk it down on the table on Day 1.