The reason classical music is less popular among the masses is not that it does not appeal to emotions - a lot of people would argue with that. Half of the story is indeed in the conservative nature of it (my father is a musician and I know how he goes about interpretation of classical compositions, stage appearance and all these rules). But there's also another half of the story which is simply lack of education in…
There is also the barrier that it is hard to write classical music. Anybody can pick up a guitar, learn I, IV, V chords and write a song (these days, the lyrics don't even need to rhyme). Fewer people can add harmony, and very few can write counterpoint. I think a classical music piece can take as long to write as a short novel.
I suspect that classical music was never all that popular: the upper classes enjoyed classical music and the more numerous lower classes enjoyed the pop music of the time from traveling musicians. It's just that the traveling musicians didn't write their stuff down.