So tell me what was the reasoning behind to remove headphone jack...

So tell me what was the reasoning behind to remove headphone jack? Is there going to be microusb headphones/iem's or what?

Wireless. Mobile devices of the future will not have connections just for headphones. It would be a waste of space. You really think in 20 years you'll still be plugging things into a 3.5mm jack on a phone? Think again.

I think the official excuse was thickness of the phone? tbf, if they put two usb-c connectors on a phone, I'd be okay with the TRS jack going away

Do you really think people want to charge 50 different devices in 20 years?

Several reasons.
1. They want make thinner and thinner phones.
2. You can't environmentally seal a headphone jack.
3. Closing the 'analog hole'; with only 'authorized' digital-only devices they can enforce DRM 100% of the time (well, at least for non-technical people, the rest of us can hack things and still create our own 'analog hole' to copy things).

There needs to be real major advancements in battery technology this to really happen. I don't want to charge some IEM's every 2 hours.

"Because Apple did it". Sensible manufacturers didn't remove jack.

They said the same thing about USB connectors.
This. If they're going to be stupid and just start taking features away in the name of "progress", at least give me a trade off. Bluetooth headphones are shit. I don't want yet another device that requires charging before I head out the door. Just give me a secondary USB C port. If everyone started doing this, we'd start seeing a lot more USB C devices.

Do you really think charging devices is going to be the same as it is today in 50 (FIFTY) years? Think, fucking think for 3 seconds before you post.

Apple definitely thinks that, and everyone else will just copy whatever they're doing.