Gayspeak
Part of this may be the homosexual dominance in fashion and trend setting, just like they are the reason fashion models are overwhelmingly women starved to look like adolescent boys and why a “androgynous” man (with plumbing) is being heralded as one of the hot new models.
Another reason would be the rise of neoteny, the worship of youth. I was struck by the difference between new and old Christmas songs. Bing Crosby and other classic male voices were deep. All of the newer songs had higher pitched boys’ voices, approaching the female range. So even the boy band celebrities have higher voices than the musical stars 50 years ago.