

Given that we’re discussing the behaviour of phones, I’m quite certain that there was never a time when they generally had line out ports. Also, I can’t imagine people are connecting their Bluetooth speakers to the wrong interface.
What you’re describing is still wishful thinking, because there’s no world where every consumer device is going to have accurately calibrated volume regardless of whether there’s a protocol which specifies it.






The UN doesn’t have any particular claim to the word “international”, except insofar as anything they do is international because the UN itself is international.
Other organisations, or even loosely affiliated groups of nations, can do international things because the word just means something like “between nations”.