I get the feeling we may at some point have the 3.5mm jack return.
There's a lot of things happening in tech that I see sort of regressing in future, not just in smartphones a number of areas like Car infotainment systems that include climate control in the screen, etc etc... There's just some old school stuff that should be left alone until a real and proper replacement is found.
Nothing has truly replaced the 3.5mm jack. The amount of times I have forgotten to charge my headphones and have had to go back to wired ones while the BT ones charge has had me just leave my BT ones at home lately.
In actual fact in the last 2months I have been so busy that I have simply been using the wired headphones, my BT ones have been sitting in my laptop bag, still dead from the day I used them until they ran out of battery and I have been too lazy to pull them in when I can just take out the wired ones and play for as long as my phone and laptop are alive.