That "courage" bit may be the most pretentious and ridiculous thing I've heard Apple say to date, and that's clearing some high bars. They're a consumer electronics company, not doctors without borders.

While from a financial standpoint this would make sense, most of the guys making the executive decisions at Apple are design focused and oriented. Dropping the headphone jack differentiates Apple even more from its competition, makes the phone sleeker, helps with water proofing, makes the wireless headphones more appealing (which not only act as headphones but also communication devices). This was much more than just a financial move for Apple, and in my opinion it looks to be a smart one.

I saw it more as a push to eliminate the cord from headphones entirely. I personally hate the cord, but I hate charging bluetooth headphones even more. I hope eliminating the jack will result in better wireless headphones, but I'm not super confident that it will.

Why would they include a 3.5 mm adapter then?

The future is bluetooth, and they're not making licensing fees off that.

I guess some people will buy lightning headphones instead of bluetooth, but it should be a small minority.