As was the floppy and CD drive...
Just yesterday I was the only person at an event who was able to play some custom music our family wanted to hear because my iPhone 6 was the only phone with a headphone*
And until last year, my parents didn’t have a single TV that could support HDMI for my boys’ game systems. Does that mean Sony and MS should still support RCA output?
How is that different than the lightning adapter to 3.5 inch headphone jack that came with the iPhone for the first two years after they remove the headphone jack? It’s still available for $10.
The difference here would be removing all input ports and requiring that you stream everything via your wireless internet. Then you'd have to charge your television but only when you weren't watching it. Everyone would think that was a stupid design choice.
The iPhone comes with wired headphones with lightning and there are plenty of third party lightning headphones and there is the aforementioned adapter.