Tim Cook's Rock Center Interview

Tim Cook's Rock Center Interview
Tim Cook:

We can only do great things a few times, only on a few products.

On the sites I follow there has been a lot of talk about Tim Cook’s Rock Center interview, but I haven’t seen anyone address his comment above.

Even Apple doesn’t expect to bring out “the next great thing” at every product launch. Why is it that so many others do—and castigate them when they don’t?