Question: does Michael Jordan really cause people to buy more Nikes at least enough to provide a profit after he gets his millions? If not, not replacing him is profitable. If yes, will his replacement provide as much or more sales and profit over the cost. Likely the first answer is yes and possibly the second. Therefore, the stock will probably rise. Unfortunately this is a sad statement on purchasing decisions. Perhaps a risky one. What happens if people quit paying a premium for products just because some sports figure endorses them? Won't happen, people of the world and especially USA are to insecure and must buy self esteme.
You're right about the whole insecurity of marketing, bust because MJ's gonna quit hoops doesn't mean NKE will quit marketing him. What do you think he's gonna do with all his free time? Hit the links.