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It's official: Smartphones will need to have replaceable batteries by 2027
(www.androidauthority.com)
This is a most excellent place for technology news and articles.
I have an old LG V20 (released in 2016) with a removable battery that's just 7.6mm thick. By comparison the Iphone 14Max is 7.9mm thick, the Samsung S23 Ultra - 8.9mm and the Oneplus 11 - 8.5mm.
IMO the purpose of non-replaceable batteries is (just like everything else) profit. Companies want to push us to replace the entire phones every two years rather than just the batteries. They've been remarkably effective at doing just that.