As a former Be employee who ended up at Apple by way of Eazel, there are two ways to answering your question about the UI direction; 1. If Apple did not acquire Be, Apple most likely would not be in business or would be a much different company. 2. Assuming Apple did survive, Steve Jobs used the industrial design language of Jony Ive for the look of Aqua. Bas Ording was the primary designer of this and was directed by Steve with daily updates. The further evolutions of brushed metal, skeumorphism, etc. were all directly driven by how Steve wanted things to look with minimal input from others. The current bland minimalist UX disaster (IMHO) would probably not have happened, because for all of his faults, Steve had very good attention to detail and was in general a good proxy for the user.