But why does Greg need a cofounder?
Starting something new is incredibly hard. The default is that your company never even forms, and it's on you to overcome the activation energy. I don't think I'd have the mental fortitude to stick that out alone.
In contrast, there's nothing more motivating than working with great people (and it's hard to do better than Ilya, Sam, and Elon). Everyone brings their own core strengths to the table, and if you've picked well your own efforts will be multiplied.
Which of your qualities specifically do you feel are actually under discussion here, and how would you recommend others build, enhance or foster those qualities if they wanted to do so?
In other words, assuming someone wanted to, how would they become more "Greg?"
Do I really need to say anything more?
a) Technical support b) someone to bounce ideas off of constantly. c) someone to support the organization should he need to take an unexpected leave.