A modern cell phone is very different from the old flip phones and SLRs/large dedicated camera. Resealing modern phones after upgrades/repairs is one of the harder parts of the whole process with fiddly little sealing glue gaskets to maintain IP ratings.

Again, solved problem: https://en.wikipedia.org/wiki/Fairphone_6

'Solved' by having measurably worse ingress protection than leading smartphones?

Yes, this is solved. Samsung makes rugged IP68 phones with user swappable batteries that are thinner than an iPhone 17 Pro when factoring the camera bump [1].

It's kind of comical how accurate this comment is https://news.ycombinator.com/item?id=48807174

[1] https://www.gsmarena.com/samsung_galaxy_xcover7-12784.php

My experience with phones like that are that they tend to fall apart when subjected to impact, which is pretty counterproductive to features like, I don’t know, being able to use the phone immediately after an impact (car crash, fall).

Sony Xperia Z solved in 2013: Water jet protected & Waterproof up to 1 meter in 30 minutes