We need to get back to sensible environmentalism. Otherwise, you can justify pretty much anything.
The issue isn’t whether or not you are fine with a little bit of waste. That little bit of waste has a cost. The cost is paid by the planet, not you, if the phone just winds up ina dump. I haven’t suggested banning phones without replaceable batteries, just making sure that you or your phone manufacturer somehow pay that cost.
Focus on bigger ticket items. The elephants in the room.
I will absolutely not keep a phone any longer just because the battery can be replaced.
For a while, phones were gaining 50-100% performance per year and noticably better screens+cameras. Now it's down to a few percent and minor camera updates are the main selling point.
Reusability is about not being selfish.
If people want to buy phones with a non-replaceable battery, that is OK I guess, but we need of fee or deposit to prevent them from dropping that cost on the environment.
Edit: come to think of it, we probably also need a fee or deposit for replaceable batteries. But at least it could be smaller, since it is just for the battery. We probably don’t want a deposit for every piece of electronics, just because that would be annoying.