Yes, either EA or Apple could pull the app from sale but Apple would not approve an update to kill previously purchased content entirely. Also, EA is not relying on anyone accepting a useless update. The kill switch is already in place and it might have been there since v1.0 for all we know.
If the judgement says "kill the app" Apple will do that. They have to do that. The question remains if "killing an app" is legally possible. Considering the fickleness of music licenses and the fact that even GOG had to pull some games from the shelves of people that already owned them, I think that this is a real possibility.
rampancy: It's not so much highlighting how evil EA is, but I'd take it as a symbol of the dangers of producing and selling (and I'd say, also buying) a game which is heavily dependent on licensed properties.
This is very, very important here. Blame EA for other stuff, bad licensing maybe, but they certainly aren't happy about this happening.