What is nominally a group of individuals working collectively to solve a problem became attributed to a single person purely for marketing purposes. It is easier for most people to remember one name, or attribute an effect to a singular cause (by extension causer).
What we remember through the mists of time is not the best, but what garnered the most attention in that era. Those two are not the same, never have been. What you call genius mow was back then an influencer.
Now modern technology has made it possible for anyone to become an influencer. And so, geniuses are everywhere and nowhere, all at once. The influencers that survive into the next era (I’m looking at Elon) will be the geniuses of our time.