Well, Apple could, of course, give other manufacturers the opportunity to also release live translation.
Before we misunderstand each other:
Apple doesn't need to make its live translation available for others, nor does it need to make its headphones available for this purpose.
It's just a matter of allowing other manufacturers to offer live translation for the iPhone with their own headphones (Samsung, for example). Apple won't do that because then they would have competition and would be competing.
In my opinion, it's just a gimmick to give Americans, who are addicted to shopping and craving recognition, an excuse to buy something new.