Because if you push the envelope and make a phone that's substantially more advanced than the competition, you drive demand for your components since the competition needs them to make a competitive phone.
Dell suffers because the only innovation they every truly had was supply-line streamlining, but they've been totally blown away by Apple's Cook + the move to China, to the point that they don't have any advantages these days. They never bothered much with R&D, and now they are dead because of that.