I understand the idea that tolerating amplified sound might have some value; in that it could possibly encourage a new generation to take up bushwalking.
But I suspect that those most likely to hike with speakers are probably also more likely to be in constant connection with the digital world. The idea that you would hike
in order to disconnect might be alien to some people. I've observed groups whose sole purpose for hiking appears to be the opportunity to advertise to the rest of the world the very fact that they're doing it (constant blogging and social media posts). I wonder if constant connectivity might indicate a lack of appreciation for the more meditative aspects of hiking. But we can live in hope, and people are capable of change.
The girl guides we encountered inspired me to think about this, and find a leash for my impatience. Surely the fact that they were in the bush (even with all their noisy gear) was a better thing than their not being there at all? I think I'd rather that they get into nature and enjoy it than never encounter it. Perhaps one day they might meet the hiker who gently shares with them the notion of hiking for tranquility; and they might be inspired. (Unfortunately I won't have been that hiker. I'm sure they'll remember me as the cranky, wet blanket who spoilt all their fun.)
With regard to drones, I'm a fan of the fishing rod approach:
https://www.youtube.com/watch?v=4nVRoXbbSGc