Whenever we argue about "iOS vs. Android," what we're really talking about is whether you prefer an isolated community or a more open one. In the case for iPhones, Apple is the lone company that owns and controls it. They are the ones who develop and make all the hardware and are the ones to decide on what to incorporate into the software. All of what the iPhone offers to the users constricts people to follow the 'rules and regulations' that the Cupertino tech company has incorporated on their devices. This is probably the main reason why Android Phones are dominating over the iPhones.
The Versatility of Android phones
Android is open for everyone, where a lot of different tech companies are fighting under the same market. Though it all goes down to being a competition, it just spells some great opportunities for the users, as they are offered a very diverse selection of devices, at diverse sets of price points, that also brings along a diverse amount of features for you to weigh on.
The Prices say it all
Price-wise, Android is focusing on mass-wide, whereas Apple is settling for elite-level buyers. Let's face it, you can't get a typical iPhone for only $50, much more you can't acquire a flagship iPhone for $400. Whereas with Android phones, you are able to access a variety of cheap yet very serviceable smartphones that can do almost anything that a typical smartphone does. Like the old saying goes, "Android is for poor people," and though it's not entirely wrong, giving more people the opportunity to own a smartphone is definitely not a bad thing.
While iPhones are getting there, Android phones have already arrived (years ago)
While Apple has just recently incorporated water-resistance features with their iPhone 7, planning to adopt a more vivid OLED display with the upcoming iPhone 8, and has recently upgraded the storage capacity of its current models, Android phones already have all of these features incorporated, and a lot more, for years. Apple doesn't even (for the moment) support microSD cards, which completely limits its overall usage and would make it more isolated. Not only does android phones support this feature, but also features wireless, faster charging, dual-SIM support, dual cameras and much, much more. Truly in a lot of ways, Android phones are far better, specs-wise, than the iPhones.