Everybody loves their iPod, and rightly so. It's one of the greatest technology products of all time. The iPod experience is the sum of many parts: design, development, etc. One of Apple's biggest strengths is their ability to put all of these pieces together effectively. If the iPod was ugly, unusable, had buggy software, or felt lousy in your hands, it wouldn't be the same device; it would be mediocre like all of the other portable mp3 players that came before and after it.
On the web, shops are usually run with a strong focus on one piece of the puzzle. Some firms are development-centric, others are design-centric, others still are business-centric. A shop's core skill usually trumps everything else. Even when they hire consultants to fill the gaps in their skill set, shops tend to keep focused on their core competencies, failing to properly execute the work of the consultants. It seems to happen everywhere — even in the best shops.
So, having the best people work on the product isn't enough; to achieve greatness, there has to be tight collaboration between all parts. The developers must respect and understand the designers, and likewise. Most importantly, no one concern can trump another.