What does "taken advantage of" mean in this context? No one is forcing them to buy anything. If someone doesn't feel the price is justified, for anything, they shouldn't buy it.

All Apple products hold their price very well. I just sold an iPhone 4S for 100€ yesterday - a five year old device.

It still runs the latest iOS, albeit a bit slower. Show me 5 year old Android device that can run the latest Android version WITH CARRIER SUPPORT, without any 3rd party hacks or rooting.

Depends on how much you prefer the experience of an iPhone versus an Android. There's a reason someone might choose an Audi versus a similarly equipped (engine wise) Volkwagen - it's a different experience, at a price, that some prefer.

Are they? Flagship models from the competition always cost about the same, especially on monthly plans.

The only iPhone (actualy iOS device of any kind) I've ever bought that's not still in active use is my first, a 3G. My daughter still uses my 3GS to this day. The screen is cracked, but it's fully functional and she can even still download compatible apps from the App Store. Even ones that are no longer available for sale, but which I bought back in the day (I'm thinking of Lemonade Stand).

I've got excellent value for money from every iOS device I've ever had, with regular software updates years after they were bought.