When the universe needs something, a desire is instilled to discover, invent or create it. If one person who is called upon to do the actual discovering, inventing or creating doesn't complete it in a timely manner, another or others are called upon to complete the work.
There are streams of consciousness in the universe. When someone discovers, invents or creates something, often someone else discovers, invents or creates something similar and often at the same or nearly the same time.
In order to get one of the greatest inventions of the modern age, in other words, we thought we needed the solitary genius. But if Alexander Graham Bell had fallen into the Grand River and drowned that day back in Brantford, the world would still have had the telephone, the only difference being that the telephone company would have been nicknamed Ma Gray, not Ma Bell.
Source: Annals of Innovation: In the Air: http://www.newyorker.com/reporting/2008/05/12/080512fa_fact_gladwell