Mark Kawano, who spent 7 years as a designer and designer evangelist at Apple, was interviewed by Co.Design about Apple’s design culture¹.  “4 Myths About Apple Design, From An Ex-Apple Designer” is a great article about how Apple delivers great products.  I think that this is a great point:

It’s actually the engineering culture, and the way the organization is structured to appreciate and support design. Everybody there is thinking about UX and design, not just the designers. And that’s what makes everything about the product so much better . . . much more than any individual designer or design team.

If your UX team are the only people who care about the user experience, you’re not going to deliver a product with an awesome user experience.