Market share doesn't help the individual companies, except in the indirect "a rising tide lifts all boats" sense.
What you SHOULD be noting is that 51.7% of the smartphone users in the U.S. are split among a half-dozen manufacturers, while ONE manufacturer, Apple -- even WITH significantly higher prices for a given feature set -- has northwards of 40% of the market to itself.
AND Apple has higher margins than Android handset manufacturers can generally claw out while trying to differentiate their offerings from the Android handset on display next to it at Best Buy or Wal-Mart. And it's MARGIN, as has been pointed out, that gets money-men wet.
Now, none of this means that Apple will ALWAYS have that sort of market share to itself, or that it will ALWAYS be able to make those sorts of margins, but as with any war of attrition, they only have to do it long ENOUGH to drive a couple more of the mid- to large- companies out (vis. Sony) and watch the Android market fragment further as smaller companies try to fill the (perceived) gap left by the big boys' exit. If Apple ends up with 30% of the market but keeps their margins up, while a dozen or more companies are splitting Android's 60% and driving their own profits (and, hence, their attractiveness to investors) down to do so, then, even -- with loss of market share -- Apple wins.