The headphone jack was putting the additional risk on your device to be crushed.

Can you expand on this? I'm assuming the force required to collapse the 3.5mm cavity would be incredibly high.

  Jacks themselves were good spots to break due to mechanical stress, especially the cheap ones.

The same can be said about the lightning connector.

  It was literally stopping any innovation. Without the jack, new alternatives will pop up at an incredible pace.

This is forced obsolescence. Suppose the jack remained in iPhone 7. Apple would have a much harder time selling wireless earbuds.