No shortage of waterproof and water-resistant headphone jacks on the market. This argument was always a red herring.

It’s about DRM and vendor lock-in, nothing more and nothing less.

What DRM?

You can make the signal encrypted all the way to the approved Bluetooth device, making it harder to extract audio to a raw format if it's played on a phone.

Samsung has done just fine with waterproofing and they've kept the headphone jack.