From Playing The Long Game Inside Tim Cook’s Apple by Rick Tetzeli, writing for Fast Company:

It’s entirely possible that Apple will never introduce a product as universally desired as the iPhone. That doesn’t mean it won’t continue to be a great company. “The iPhone entered a market that was the biggest on earth for electronic devices,” Cooks tells me, as we’re wrapping up our interview. “Why is that? It’s because eventually, everyone in the world will have one. There are not too many things like that.”

I’d argue it’s more likely than not that Apple, or any company, will never introduce a product as universally desired as the iPhone. I’ll go even farther and add that using the success of smartphones as any sort of bar to measure success is folly.