Those of us who follow this sort of thing learned early on that the iPhone 7 would not have a headphone jack. Which began the season of speculation about what Apple's justification would be for the making change. Jason Snell was especially vocal about this:

To me, that’s the single most interesting bit of stagecraft and script that I’m expecting Wednesday. Not the removal of the headphone jack itself, but how Apple spins the benefit to users who will have to deal with adapters and short-term incompatibilities if they buy a new iPhone. We can endlessly argue about why Apple should keep or remove the headphone jack; what I’m interested in is which argument Apple chooses to make.

As was Marco Arment:

There are clear benefits to Apple — minor savings in parts and internal complexity, some profit from adapters and Lightning licensing, and driving a big Beats upgrade cycle — but nobody has come up with any compelling benefits for customers that require removing the headphone jack and can’t already be done in today’s iPhones.

Now that we are living post-headphone-removal-Apple-Event, discussions have turned to whether or not Apple has successfully justified their decision. Some have been satisfied with Apple's given reasons, others have not. (And others are  just feigning outrage at Phil Schiller's "Courage" comment.)

But I offer that there is another way to look at this: Apple doesn't have to come up with any reason to justify removing the headphone jack at all.

They have to justify keeping the headphone jack.

iPhones fit in your pocket, are getting more powerful and gaining more functionality every year, and are getting thinner every couple of years. Every last feature of that device device needs a very good reason for being there, otherwise it should be gone. 

And between being able to play audio through the lightning connector, Apple's goal to make the iPhone more water-resistant, and their belief that wireless headphones like AirPods provide a superior experience, the reasons for keeping the jack around just weren't there any more.