Gygax himself said that he felt he was in a hurry to publish because others were also experimenting with the same idea. Not sure where I read that. Maybe someone here knows?
If you're looking for sourcing from that time period, I will recommend reading Game Wizards and The Elusive Shift, which should provide some better overall insight into the general gaming zeitgeist.
That said, this is why I try to avoid counterfactuals. If things had been different, maybe they would have been different. But we only have this one reality at present that we can examine, and in this reality, OD&D was the first TTRPG, and its impact cannot be overstated.