This was interesting - Keep in mind there is a massive difference between PhD's/DMA's that are performance oriented, and PhD's that are purely theoretical. While both require a near equivocal amount of research, only one degree, the performance requires an extremely high standard of performance to get the degree. You'll find these people who based their higher education on performance are more open to differing genres, styles, levels and often are open to change.
Those you speak of are more often than not, musicologists, ethnomusicologists and theorists. The music they write you'd be surprised. Sometimes it's actually good. But your observation is accurate for many who never bothered to hone their performing skills.