It's interesting that you use Elon Musk as an example, since Max Levchin's interview in Founders at Work suggested that his only contribution to PayPal was to attempt to get them to switch all their servers over to Windows.

(Levchin, BTW, seems much more like someone who actually "gets his hands dirty" - which doesn't actually work out all that well sometimes, as evidenced by subsequent ventures like Slide that executed really well against a pointless market.)