I don't think Apple has much to change on their current iPhones and they don't have much hope for innovation in the future so I think in time the cheaper Android and Windows phones will win favor. I believe their price point will make this happen quicker, as Apple always held their products to higher than average prices.
The iPhone was all the rage and everyone had to have one or at least everyone who could afford it.
Now that there are less expensive options that are just as good we will see less of the the iPhone and more of the others. Technology is evolving to make this a reality.
The iPhones exist because they are down to earth and extremely simple to maneuver and get around. I personally like Android a lot better, but there is a reason Apple's stock is always so high and they consistently sell more products than any other. Also, there's a reason why everyone on the planet seemingly has an Apple product.
iPhones may be more expensive than Windows phones or Androids, but iPhones will dominate the market because they are the brand leader, simple enough. They have sold themselves on being more attractive, more sleek, and in general just plain "cooler" to own. They can even justify their high price tag by suggesting that the Windows phones are nothing more than cheaper, uncool alternatives to their brand.
No, inexpensive Android/Windows phones will not outsell iPhones, because people already like using their iPhones, and there is a great deal of brand loyalty with the iPhone. Also, some people are skeptical that the Android will perform well, because Windows as an operating service tends to have a lot of glitches, and people don't want the same for their phones.