I mean, that's a valid way to view it, but I doubt it was an engineering decision first and foremost. Hanlon's razor applies: 1) Apple makes a ton of money from selling AirPods and 2) this decision was made during the Jony Ive era of "remove literally everything that is not strictly necessary just because fewer ports is more aesthetically pleasing". Under these conditions, of course they would remove the headphone jack. It's Apple doing Apple shit.

But: people used the same arguments -- less ports saves space, who needs it, etc -- to argue that the HDMI port, MagSafe, and decent keyboards would never come back. But they did, in MacBooks that were thicker than the previous generation. Sometimes you can teach old dogs new tricks.

They could have polled the market to see what it wants: release an iPhone that has a headphone jack and is slightly bigger if needed, and a slim one that doesn't have one. This will never happen, and that is my point: you or I will never know if people care, because people never had the ability to choose.