Something that I haven't seen mentioned on this topic:
having a spare charged battery with you also have so much more sense than carrying a powerbank. No losses transferring power to phone, no excessive heat, MUCH lighter.
This is what we have for radios (walkie-talkies), drones, cameras, but not for phones, where we really need this.
We're not necessarily talking about "pop the back open and slam a new one in" batteries a la Nokia 3310, but rather being able to replace a battery at the end of its lifecycle without special expertise and tools, but still, with some amount of effort required.
That's the requirement at least, but companies are of course free to choose either approach.
According to a draft version of the ecodesign regulation on the EU’s website, batteries should be replaceable “with no tool, a tool or set of tools that is supplied with the product or spare part, or basic tools.”
I'm daydreaming about potential feature and sell point some manufacturers may adapt to bring this regulation further into a win-win for themselves and customers. So yes, essentially bring me 3310 back :)
But when Apple ships the replacement battery with the Apple self service tools that they have today. Would that even change something for the iPhone? The amount of expertise is questionable.