There is no “scientific” explanation, there IS a psychological explanation.
Everythings newness wears off eventually and humans crave new experiences, sensations, stimulation.
Ego is responsible for a never ending quest of new, exciting, and stimulating experiences.
The music itself does not become boring, it is neutral, it is the mind that loses interest.
Learning to see with new eyes or listen with new ears is the ticket.
This is true for many things.
I live in the hills and have deer in my yard everyday, I hardly notice them anymore but to city friends that come up here it is a wonderland to them and everything I take for granted, deer in the yard, horses hanging around, the beauty, blows them away.
It reminds me how much I take for granted my lifestyle and helps me remember to really keep “seeing” with new eyes.
Boredom is a state of mind not an actual condition.