What are the tradeoffs for a user replaceable battery? (really, this is something we should all know if we are arguing FOR replaceable batteries - maybe it's not the best idea?
I would wager 99%+ of sales go to people who never want to touch the innards of a phone.
And anecdotally, my SO's father got a cheap battery for his iphone and it ballooned up and almost destroyed his phone.
He also asked me if he should get a 3rd party power adaptor for his macbook (I said no, he ignored me because his wife is cheap), and it was this cheap POS that actually ended up forcing him to doa $600 repair AND get an apple power supply.
I spent years working on consumer PCs - normal people dont have time or inclination to deal with all this crap, just like they don't want to learn to repair their own air conditioner.
Consumers who want/need easily replaceable batteries already don't choose an iPhone, so all this in mind, I suspect the numbers don't add up for this argument.