I have an iPhone 4S and a Samsung Galaxy Note 2 smartphone. They are both good phones and iOS and Android are solid platforms. It doesn't matter which of the phones I take with me when I head out the door for the day, either one will serve me just fine.
The fact is, smartphone operating systems have evolved to the point where any of them can meet my needs, and probably those of most folks. They handle phone calls and messaging pretty much equally. That includes text messaging, email, and in most cases video chats.
When it comes to most common functions, there's not a lot separating the major platforms, and that includes iOS, Android, Windows Phone, and BlackBerry. They run the phones that use them handily, in a way that will satisfy most customers.
Not all of the platforms have the major apps that people want, and that can be a factor in choosing which one is right for a particular user. Even so, many apps interact with online services, which can be used through a web browser. That's something all the platforms handle very well, so the lack of an app may not be that big a deal.
I am certain that I could pick up a phone on any of the four major platforms and have my needs met. I'd use the apps I like if available, and the web browser for those needs where an app doesn't exist.
I don't think I am unique in this, I feel confident that a great many users would find that any of these platforms could handle what they need. There is no longer a big difference in what any of the phone platforms can do. The major stuff works just fine on them all.
Sure, there are some functions that vary among the platforms and those might be important to some users. That would restrict using one or more of the platforms, but I have a feeling those cases are not as common as many believe.
All of the platforms have an ecosystem for apps and content, and those heavily invested in one won't want to change and that's understandable. Others could jump ship midstream without missing a beat.
Existing ecosystem investment and special apps aside, many could move from one platform to another and find their needs met just fine. Brand or platform loyalty aside, if folks would try the other platforms they might be surprised to find the other operating systmes could handle everything they need without issue.