A professor at Yale demonstrated playing original music on muscle memory alone. This was in a music theory open-courseware that I was watching. With muscle memory, your fingers play notes in a manner that's somewhat guaranteed to be melodic. Although the music might be original, it's not likely to be a hit.
Similarly, the statistical approach used by "AI" to create original music is like muscle memory. They're a combination of what's already known, but not necessarily a hit original composition. While you can "interpolate" good-sounding tunes, you might not extrapolate to something new that sounds amazing.
In AI, as in music, muscle memory is not a substitute for creativity.