Carter hardly qualifies, since it was really 2 assets, not anything resembling a bunch. I said almost never, because I had thought of Pronger too.
There are plenty of examples of it not resulting in Cups... starting with Gretzky to LA. Sometimes, the big name being acquired is young himself, like Eric Lindros. We also traded 4 quality young/future assets for Nash. Jagr to Washington. Thornton to San Jose. Kovalchuk to NJ.
Maybe it's just a perception in my head more than a statistical reality, but I just don't think it works out the way teams intend very often.