You can't have the thinnest/sleekest possible phone and an easily removable battery. Have to choose.
Frustrating thing is, mainstream phone manufacturers don't give you a choice. There's no option to buy e.g. an a slightly more ruggedized iPhone that is 15% bulkier but gives you easy battery access. That's a thing I'd buy, even if it cost a bit more.
The quest for "sleekness at all costs" made more sense 15-20 years ago, when full-spec smartphones and laptops were clunkier.
Hopefully the tide is turning. Apple is offering beefier and thicker laptops (M1/M2 Macbook Pros) and likewise now gives buyers an option for a beefier "Explorer Edition" watch. No battery access sadly. But hopefully the pendulum might swing the other way a little now.
https://www.samsung.com/us/mobile/phones/galaxy-xcover/galax...
Edit: This is getting downvoted, but it's a regularly-updated phone line from a mainstream manufacturer with decent specs. You can absolutely vote with your wallet here as OP laid out.
Is this true? Plastic covers seemed thinner than the glass/metal shells that have replaced them. Also, from my limited experience, the batteries in the glued-together phones have adhesive strips that secure them inside the case, which again add a little extra thickness.
I could be wrong about those things, but I stand by my assertion that the plastic snap-fit phones were more durable. Durable enough that they didn't need cases for protection, which above all else rob a phone of its thinness/sleekness.
The first time I dropped a glued-together phone, I cracked the screen. I thought it must have been a fluke, since I'd dropped plastic phones tons and they'd always been fine. I was so sure it was a weird one-off I refused to get a case after having the screen replaced. My girlfriend called me an idiot. Two months later, I dropped the phone again. Now I have a case.
Why not buy a $100 rugged waterproof case and an external battery?
A 25% bulkier "rugged" iPhone 15 Pro would still fit nicely in most people's pockets. Unlike an encased iPhone plus external battery pack.
Like a lot of men, I carry a phone and wallet in one pocket and my keys in another. I don't typically carry a bag. Not gonna carry a battery pack too.
Also, an external battery pack achieves one thing (extended battery life) but not the other -- still wouldn't be able to easily replace the internal battery once it has aged out.