Because intent literally has no effect on the quality of the music?
It has a huge effect, especially on vocals. There are many vocalists who, while technically hitting all the notes perfectly, sound more bland and uninspired than others.
It heavily affects songwriting as well, that's why there are so many 4 chords famous pop songs that sound basically the same. It's because as they were writing them, they based them off a certain formula, that proved to be successful before. There was little to no creativity in them at all