It's official: Smartphones will need to have replaceable batteries by 2027
(www.androidauthority.com)
While I do agree that we need more modular phones, laptops, etc. having a replaceable battery would prevent phones to be fully water proof.
But I do agree with you, I have a 2-year old phone and I already experience the battery degradation. I would most likely use this phone for another year, max two, but then would be pissed by how often I need to charge it and start looking into purchasing a new one.
Planned obsolescence is definitely a thing that enriches corporations