If something has value of its own, then it will be purchased regardless of whether other unrelated products are or aren't purchased.
Thus, in order for people who don't find iPhones particularly valuable to contribute zero market share to the independent market for phone software, it can only be the case that phone software has no value.
It will only be purchase by people who can afford it and who find it worth the price. If someone doesn’t purchase it, there is no implication that they see zero value in it.
Thus, in order for people who don't find iPhones particularly valuable to contribute zero market share to the independent market for phone software, it can only be the case that phone software has no value.