It existed at all because Steve Jobs convinced the people working on it to believe in it enough to care. This is really rare, most people don't care (and are rational not to) but it is required to make any great product
Or rather, because Steve took great care not to hire the bozos most companies are staffed with. This is an extremely difficult and underappreciated thing to do, and Steve himself failed spectacularly at it on at least one occasion (which probably made him even more cautious).