Personally I’m confused why people say they want a thinner phone while carrying a phone that’s keeps getting larger every model.
When was the last time you kept a phone longer than 2-3 years? That’d explain why you haven’t had one die.
Assuming you do get a new phone regularly, easy battery replacement will probably help the resale value of your own a fair bit - the labour cost of a battery replacement is priced into most older phones on the second hand market.
I've had the same phone for over 6 years now (iPhone 11). It's a bit slower now, but I suspect that's more to do with software changes than anything else. In particular the battery is still in pretty good shape.
My average time on a smartphone is now at 4 years, feels like it's going to 5 pretty soon. [Last upgrade was for USB-C. Next upgrade will be for on-device LLM. It's wild how approximately 0% of what Apple has done outside of the USB-C connector has mattered to me in the last 10+ years - low-light photography is probably the only other thing that comes to mind. ]
I've had two battery replacements since 2015. One of them was required, the other was mostly optional (battery had dropped to 90% on my iPhone - which was probably sufficient).
USB-C - that was an awesome requirement that it was unclear whether Apple was ever going to do.
User Replaceable Battery? Zero desire, particularly if it reduces water resistance on the device. Dozens of things I've wanted from a phone - being able to replace the battery has never even entered my mind as something I wanted.