Currently, the Lightning port is used for charging, compatible wired earphones, and for recovery/DFU mode via Mac or PC.
- For charging: We can use a wireless charger (though currently, it is not efficient. it also affects battery life.)
- For audio output: People are already flocking to wireless solutions. So, we can safely ignore this.
- Recovery/DFU Mode: There are reports that Apple is already working/testing a method to perform iPhone recovery over the internet. On Mac, you already have internet recovery. It is a matter of a few years (max) until we have the same for iPhone and iPad.
So, in short - Yes. Five years from now, when wireless charging gets efficient, and Apple figures out a reliable way for over-the-air recovery, it is definitely possible that we get iPhones with no ports!
Let us see what the future holds.
Hope it helps!