Market share is like "users" in a startup, it means nothing. Revenue is everything. Sometimes, market share is directionally proportional to revenues, in the phone wars case, it isn't.
Does any one really think Cook is loosing sleep at night because he wants customers from "android's share"? He wants users from the rite market segment aka the ones who spend money. I'm going to go out on a limb here and say they have quite a bit of those types.
-- Edit: spelling