As long as Apple create a 3.5mm to USB/thunderbolt connector for the Mac when the Mac loses the headphone port, I'll be happy.It's a logical step.
You can come up with rationalizations to keep old technology around pretty much forever. But at some point, you've got to move on. And I think Apple did the right thing with the iPhone phono jack.
The phono jack is (mostly) unidirectional. And it's analog. It adds weight, volume, and a potential ingress point for moisture into the phone.
Is it going go cause some degree of complication for people with a lot of investment in old-school technology? It'll cause some. I'll need the little adapter to use my noise-cancelling headphones. But I suspect that sooner or later I'll update the phones to ones with Bluetooth built-in.
A word about Bluetooth: I've been using it on-and-off for several years now. It's gotten better, but it's still not where it needs to be for high-fidelity music listening. It's laggy. Pairing is a nuisance. And there's another battery life to keep track of. The Apple air Bids supposedly solve some of these issues, but still....
Embrace Change.