I don't think the ad agencies "get" Apple anymore. Maybe they never really did. A lot of the ideas that seem to have come out of outside ad guys have been pretty awful lately. It seems the only Apple ads to work well are the ones you find out later Apple took over creative control to make.
Then you've got those emails that came out in court, between Apple execs and their agency. Shows the ad guys have no freaking clue.
So good, Apple will do it all in-house. They probably should've been doing that all along.
And for everyone worried about Apple hiring marketing guys instead of engineers, it's not like Apple is strapped for cash, and it's not like they weren't hiring outside marketing people anyway. They're just shifting it where they have more control, where they can fire people that don't work out, and in the long run it'll probably be cheaper. Would you rather pay an ad company looking to make a profit, and doesn't understand your business, or would you rather pay your own guys internally, who you can train in your culture, and keep the profit yourself?