Any company that makes it big has a growing period when their founder departs. Many investors call it "sending the kid to college" as in can they take care of themselves and grow.
Companies that thrived after their founders left are the likes of Disney, Ford, Westinghouse and others. Some of the corporate graveyard that did not do well after the founders left are Palm, 3Dfx, Caere, Amiga and others.
My take is that Ive, Cook and company have a very good team to continue Steve Jobs legacy. Their may be some bumps in the road, but I see the company as a good blue chip buy for the next decade.