Music is the medium from which all societies define themselves, and throughout history has always been a way to express our emotions, so music represents humanity, we can agree on that, but is music becoming happier?
If you ever listen to a song from say 30 years ago, the tones are duller, and they tend to be talking more about problems, examples are artists like David bowie and Madness, both of whom made millions, but if you listen to their music now, you might not like it as much, mainly because as society changes, our feelings towards that society changes, and thus our feelings and emotions around music also changes, sure there are still sad songs, but they aren't like they used to be, and lots of new songs now seem to have a happier tone, at least the really popular ones do.
So if there's a direct link between people's general happiness, and the tone and sound of a new released song, we can agree that music directly represents how we're feeling, based not just on words, but also by what tones and pitches the song reaches, meaning if music you hear is happier, and the songs you hear are jollier, it might mea society as a whole is becoming a happier place.
I'm not finished though, you might also recieve smaller undertones of sadness in a song, even if its a really happy one, so could that then releate to a society, of which seems happier on the surface, having sadder and smaller amounts of hidden feelings, things which are shunned under the metaphorical rug to be hidden, maybe? if so, by listening to today's music, what do you feel society is like, are we happier, or more tormented than before? and if so, how and why?