Earlier quoted context omitted.
Phone batteries are replaceable. Just not directly by end-users (well, not most end-users). There are design tradeoffs to make the batteries user-replaceable. E.g., the batteries are going to need a casing and socket that make them OK for users to handle and replace. The phone's going to need additional casing pieces, latches, and seals, etc. The phone's going to be a little bigger, heavier and more expensive. Maybe…
> Maybe not a great tradeoff for something needed once every 2-3 years. The case for user-replaceable batteries isn't just to be able to replace them when they wear out. It's also to be able to carry a spare or two for when you want to use the device for an extended period of time. (No, external power banks don't really address this use case).
Can you elaborate on why not? For me they address it far better than swapping out the internal battery, since you don't have to interrupt that extended use by powering down the phone to make the switch. They're also way easier to recharge simultaneously, without needing a bank of dummy phones.