"Ruggedized" gear is a requirement here. Emergency services radios need to be very solid, and very easy to use — you're always working on something else and quite possibly life-threatening, and the radio is a tool.

If you can drop it, slam it, whack it, rain on it or even dunk it, cover it with blood or vomit (and clean it), balance your weight on it on a stairway, use it as a wheel chock (unintentionally) and (depending on the particular users) operate it with your gloves on, then we'll talk.

For some users, you further need to allow for heavy gloves.

Or provide emergency buttons, or other features.

As great as it is, iPhone isn't close to providing this.