It isnt that hard to deal without the headphone jack. Just buy a cheap set of bluetooth headphones and be good. If battery is an issue, make sure you look at how long the battery is rated for. It isnt hard to find a set that has a music playback life of 10+ hours. Hell, my $30 pair of HDMX Journey lasts that long. Sure they dont sound the greatest, but its more than enough for use at work or when doing things outside.
The 3.5mm jack is over 100 years old from what I understand. Technology moves on, changes, evolves, and improves. Things change because people need things that can do more. At the time, 486 computers did what they needed to do just fine. So why did we improve on this if it was good enough? People wanted to do more, faster, and the 486 became very limited very quickly. The 3.5mm jack has hit its limits (probably hit its limits years, if not decades ago, but we kept using it because nothing better existed) and now we are moving on to wireless technologies for them - namely Bluetooth. Even if Bluetooth is not at the moment capable of the same audio fidelity that the 3.5mm jack is, it bet it wont be long before it is. Not only will that improve, but battery tech will improve so we can go from charging them once a day to once a week.
It also seems like it has been forgotten that Apple was not the only one, and not even the first to remove the 3.5mm jack from their phones, but are getting the most flack for doing so. For myself, it doesnt even matter. I switched to bluetooth headphones before the jack was even removed because I love the freedom they give not being tethered to the device any longer. No more unruly cables to deal with getting in your way and getting caught on things as you move around and having the headphones yanked out of your ears and/or yanked out of the jack on the phone.
To me it makes sense to remove it, and I honestly see the charging port going the same way once wireless charging becomes good enough and really comes into its own.