I listen to a fair amount of choral music, from plainchant and organum up through modern and contemporary works. I think the short answer is missing, which is that most choral music just isn’t that exciting.
The Wikipedia article for the Motet has an interesting quote which echoes the sentiment here:
> [the motet is] not to be celebrated in the presence of common people, because they do not notice its subtlety, nor are they delighted in hearing it, but in the presence of the educated and of those who are seeking out subtleties in the arts.
This quote is attributed to Johannes de Grocheio in the 1200s! That means that people have been saying that choral music is hard to appreciate for more than seven hundred years.
The Wikipedia article for the Motet has an interesting quote which echoes the sentiment here:
> [the motet is] not to be celebrated in the presence of common people, because they do not notice its subtlety, nor are they delighted in hearing it, but in the presence of the educated and of those who are seeking out subtleties in the arts.
This quote is attributed to Johannes de Grocheio in the 1200s! That means that people have been saying that choral music is hard to appreciate for more than seven hundred years.