Repairability was bad but has gone up a lot, they did a big internals redesign for iPhone 15 to make it easier to swap batteries and replace screens. Still not something they want user serviceable, I imagine mostly because it creates headaches for everyone involved. Most people struggle fixing big things, let alone sub-mm precision things. But this helps the 3rd party repair shops a lot.
And at the time they were comparable to a flashlight in terms of complexity, not running AAA games with raytracing and a camera pipeline of untold complexity. It’s almost like having anything this complex working requires insane engineering and miniaturization, this is not due to “planned obsolescence”, especially if you take a look at the second hand market. No other brand has even remotely similar resell value.