Considering you can use a lightning or usb c to 3.5mm with a built in DAC that sounds as good or better than the ones they were putting in the phones, the 3.5mm jack was pretty redundant.
https://www.youtube.com/watch?v=utfbE3_uAMA
So I call BS on space constrains, I call BS on waterproofing (waterproofed phones with 3.5mm jack exist). Conveniently, when Apple released iPhone 7, they also released 1st gen AirPods :-)
Then stop trying to make paper thin personal devices.
I think the industry is hostage of some "visionaries" thinking hey will eventually make movie-like holo devices with no need for electronics, while the reality of engineering is much more complex and laden with trade-offs.
Strip the phone down to the bare minimum. Obviously they just want me to buy a separate pocket PC instead, and only use the phone for emergency calls and businesses that don't have websites.
Back to the dumb-phone days.
They're both next level when compared the the capabilities of a smartphone. The camera has Zeiss lenses, has amazing optical zoom, all kinds of manual and automatic modes, and takes far better night shots than any phone. The media player's battery lasts weeks, plays every file type, and has actual hardware playback buttons and a volume knob. Oh, and it drives all kinds of nice headphones perfectly well.
And neither of these devices interrupts me with notifications or demands any amount of my attention.
I don't think I'll get another smartphone until I absolutely have no choice. It's better for my mental health anyway to not have some magic device that I rely on for everything and I can't stop pulling out of my pocket whenever my brain needs stimulation.
Not to take away from your valid experience but my phone doesn't interrupt me with notifications because I turned off everything I am not 100% bothered about (which leaves just a couple of messengers, phone calls, and bank transaction notifications) and all those are silenced 2000-0800 (or during workouts.)
Dumb phones had headphone jacks