Anecdotal example: I recently purchased headphones for my 65-year old father and showed him how to use it, in preparation for his "headphone jack-less" future. After about a month (he lives in China, so I see him only a couple times a year), I asked him how it's going and he said he doesn't use them anymore because he just couldn't figure it out. I tried to explain "Turn on Bluetooth on your phone, then turn on your headphones, then hold down the button to pair, etc", but it was actually quite complicated because once he did this dance, 2 months later his phone restarted and bluetooth was off and we had to do it again. Software-wise, I can just send a link, but when it comes to hardware + software like printers, things become really challenging to explain.
I bring this up because if we're moving to the "wireless" world, we need to really consider accessibility for the elderly. My father ended up throwing away these really expensive Beats headphones, went to his local market and bought some cheap Sony headphones and is now listening fine. I'm not really sure what's going on happen when his next phone doesn't have the headphone jack.