> if apple made a phone with replaceable batteries with a bit more thickness and some compromises on water resistance vs. cost, you'd actually see the consumer preferences play out.

We already went through the period of offering both and people preferred the thin hard to repair slabs we have now. There were quite a few phones made during the transition to the current state and the overwhelming purchasing choice was eliminate replicable batteries.

I'd love it if we could make slightly thicker phones (I put cases on my phone still I'm not chasing absolute thinness contrary to your assumptions) with the same battery capacity and feel, but there's a lot more of a trade off than just a little thickness when you go back to the old replicable battery. You lose a lot of capacity vs volume when you make the battery removable because it needs it's own plastic shell and you have to have a water resistant cavity to insert it into. Both of those eat up probably 10-20% of the capacity you can place in the same area with a bare(ish) lithium polymer pack that goes into the current design.

It's nice to believe people would agree with you if only they had the choice companies have stripped away from them to make again but it's not like people didn't have a chance to buy repairable smartphones over the current version already.. Most people just don't really think about replacing their phone's battery ever until it's a problem.