Very interesting thread, gruhche!
When you say you're talking about Chanel "still making most of its
money selling the bag, the jacket and the perfume that were launched half a century ago....", I kind of see this as a matter of branding. In other words, Chick-fil-A is still making millions off of their classic Chick-fil-A chicken sandwhich. May sound like a silly comparison, but it's true. (By the way, anyone ever had their Chicken mini's for breakfast? They are sooo yummy. But they really are nothing more than chopped up Chick-fil-A chicken sandwhiches, LOL!!)
Some of the products people may feel a business keeps reinventing and reselling to their customers as a different product are being reinvented because the product is necessary to keep (the company's branding was built upon it and their client-base demands it), but the packaging (for instance) may need updating to give it a more "up-to-date"/current look.
I hope what I am saying makes sense...I may be back with more comments/clarification later...