I hate that everything useful is being thrown out the window for "water proofing." Fuck that, people need to quit being so lazy and careless with their shit.
And I'm calling bullshit on the dust thing. I'm not saying it's a negligible consideration, but it's not something they need to start gelding features for. That's just a horseshit excuse to effectuate planned obsolescence and sell you overpriced accessories.
I still use an 8 year old phone with a tool-free replaceable battery, headphone jack, and microSD slot. I live in the country, there's dust everywhere and it would be dead by now if dust was such a problem.
Look I live in a place where we get sideways torrential rain. Often. I need my phone to be waterproof enough to survive my commute to work on a bad day
This defense of feature removal always conveniently ignores the phones that manage to accomplish fantastic ingress ratings even with headphone jacks, SD cards, etc.
It's not because of water/dust. It's purely cost cutting.
That's not quite true: other parts fail more often. I've never once had a headphone jack or micro SD card slot on a phone break on me. I've had headphone jacks on other devices break, but pretty rarely. On other audio equipment, 1/4" jacks break all the time, but headphones jacks just aren't subject to that kind of force. I don't remember anyone I know personally having issues with those things. LED's are incredibly robust as long as you don't put too much current through them or invert the polarity. And you wouldn't want that much current for a mere indicator anyways.
The part most likely to break is the screen. Next is the battery, which doesn't break but rather wears. Next is the charging port (depends on the standard, but this is less of a concern recently with USB-C, Lighting, and wireless charging). Next is physical buttons (power, volume, etc). Then you start getting to the point of headphone jacks and micro SD cards. It's hard to find solid academic research, and a lot of this varies over time and by make and model, but a quick search turns up a bunch of articles from cell phone repair places that back this up.
Also worth mentioning that the CPU, RAM, and updates, along with the ever-increasing demands of apps a d websites, means phones that were powerhouses 10 years ago are barely able to do anything today even if the hardware is in pristine condition. That's a whole other problem, and others have pointed out the waste and evils of intent obsolescence. Related to headphone jacks, SD cards, and indicator LED's: that further invalidates the reliability and longevity arguments because those parts are going to last way longer than the main parts of the phone would anyways.
I'm not convinced by this argument: at the back of the phone is a built-in LED (used as the flash). Which could be used for notifications too.
Phones with OLED screens could use part of the screen as a notification as well. Both of these can be accomplished in software. Currently you have to notice that something happens as it happens, otherwise you need to at leas activate the screen. The notification LED was useful in that you could glance at your phone and see if you missed something.
I use an app on my Pixel 7 that uses a small portion of the OLED around the front facing camera cutout to generate custom colored notifications. This is similar to how dynamic island on IOS works and since I do not use the always on display it mimics an LED light for my notification needs.