It's always possible to add a battery. That's not the problem. The problem is that we have a passive device, headphones, that works well and are a stable and mature tech, that will become crap.

I dont want to charger yet another device in my daily routine. I won't, actually, and will steer away from any phone that requires active headphones to work.

I have a phone with a headphone jack, and I'm using Bluetooth headphones for hours every day. The headphone battery lasts a lot longer than the phone. In the past few years even audiophile brands have been releasing blueooth models and they are getting good.

I'm not saying I agree with getting rid of the headphone jack. The amount of utility it provides is pretty high relative to the volume it takes up.

There's also a lot of additional weight.