The only valid reason is waterproofing. If the phone isn't waterproof, it's only to limit repairability... Also one factor in that was, I believe, the thinness war, but that's pretty much over now as they all got to the practical limit I guess.
Unfortunately we still see too many people push the "but my IP rating" narrative without realising that engineers are perfectly able to design gaskets for all kinds of applications.
Some phones with removable batteries even had them and were (to a certain degree) waterproof.
The ONLY reason phones are no longer servicable is profits. Why extend a product's lifespan if you can just frustrate the consumer to the point where they will just buy another one?
Nuclear powered- or nuclear capable submarines?
Though I guess in nuclear powered submarines the "batteries" are actively unglueing themselves, which is what powers them in the first place.
I want to know what all these people are doing with their phones... I've needed a phone to be waterproof exactly one time. 20 years ago when I got chucked into a pool with my flip phone in my pocket. I've had about a dozen batteries stop charging properly and needed replacement since then.
I have this habit where I try to squeeze every bit of use out of a device until something forces me to get a new one.
My latest two phones have both lasted for 7 years, and I'm still not planning on upgrading until someting breaks.
In all those years I have never encountered a situation where I would have benefited from my phone being more waterproof than just basic ingress protection. Higher IP ratings are only helpful for those who don't want to be conscious of their possessions and want insurance in case of accidents instead of preventing the situations outright.
If we truly want to reduce our impact on the use of natural resources, we should start with eradicating the mindset that things being disposable is somehow fine.
When I opened up my pixel to replace its screen I was able to replace the lining with a fresh one. Seems like that should be possible with a removable battery as well, no?
I'm not even sure thinness was something consumers ever would have demanded (at the sacrifice of battery life) if the mfrs hadn't pushed it as a selling point.
In the flipphone days I didn't know many people who didn't have at least one spare battery, so they could swap to a fresh one on the go without having to charge, or bought extra thick batteries with higher capacity, extending the back of the phone.
Then when smartphones had removable batteries, lots of people still did those things. And all during that time I remember many reviewers and consumers reacting to many of the "thinness" claims with "I'd really like a bigger battery instead."
I also remember it being proven that apple's removal of the headphone jack impacted neither waterproofing nor thinness, despite their claims. (But then of course one by one others started following suit.)
I think it's better for mfrs and that's the only reason. It saves them money on mfr, or gets phones tossed in the bin faster. Possibly both.
I'd still take 2 or 3 more mm of thickness for an amazing battery.
I’m not even sure thinness was something consumers ever would have demanded
I am entirely convinced that most "features" on modern devices are not "something consumers would have demanded". Sure, different lenses is nice if you're a hobbyist photographer, but do most people really need more than a single back-facing camera? Do most people want to have wireless earbuds at the cost of not having a headphone jack? Do most people want glass backs and other such gimmicks that make their device more fragile? I've been told for decades that the modern economic system is great because competition forces manufacturers to prioritize what is best for the consumers. But in the context of smartphones, it feels like the roles are completely reversed. Manufacturers come up with some bullshit and then mount psy-ops (ad campaigns, online astroturfing) to convince the population that it's worth their money
About thinness:
I also like my phones bendy and snappy (iPhone 6), as well as exploding batteries (Galaxy Note 7 or 10, I don't remember the exact model tbh).
Or you have to 'hold it right' (OG iPhone).
These were all huge issues that could be fixed without sacrificing the thinness.
Thinness shouldn't be used as an excuse for otherwise shitty phones, since it's clearly a non-sequitur.
I'm not even sure thinness was something consumers ever would have demanded
Something popular back in the removable battery days was to replace them with thicker extended capacity batteries. So no, battery life was more important to a lot of comsumers.
My casio watch is waterproof. [100M Water Resistant]
And it has a user replacable battery.
With a gasket inside and cool looking screws. (yes, I consider screws to be cool)
Also, it costs less than $20
Your Casio watch also has a manual with a warning inside saying it won't be waterproof anymore after a battery replacement unless you send it in to Casio to replace the battery.
I didn't have to open it until 2x the time of official warranty.
The gasket had gunk in it on the outer side, so I cleaned it, but I could have gotten a replacement from one of the local Casio stores.
The strap has broken 2 times until now (yeah, I'm kinda rough on it) and replacing that doesn't void any warranty.
The standardised nature means, I can get either Casio branded straps (even from other models if my model is discontinued) or other generic straps.
I am nearing the point at which it might require another battery change, but either way it's worked pretty well.
I take hot water baths with it and even though I never used it up-to 100m (I'm not really into diving), I haven't seen rust or moisture in the inside.
Of course, if you open the stuff and change something yourself, it's up to you to warranty it. You can't expect them to trust every tom, dick and harry who might:
Not tighten the screws well enough
Not place the gasket back in place
Do any other random stuff
and officially say that they will cover that. I know I wouldn't.
The point is, they let you do what you want and help you at a reasonable price (the replacement straps were priced appropriately).
I can't say the same for the fancier models though.
Screws are an incredible wonder. Itty bits of metal with fine threading to attach two things? And we just produce like billions of the things? Truly amazing.
I'd love to have a phone with 8 screws and a gasket in the back cover instead of the fixed plastic latches that the Fairphone and others have.
Easily more water tolerant and love the industrial feel.
You can, but every hardware feature you add takes physical space in the phone. Making a phone waterproof requires adding stuff to the phone, which takes away space for other things. Usually battery size ends up being one of the things that takes a hit. You want a phone that's waterproof and has a removable battery? Then the battery size gets reduced by X%, or some other features people care about get dropped.