Youtube now leads in showing music videos, having been previously used unofficially by fans uploading those videos, then record companies saw how that platform is great at selling music and so they followed suit by either doing it themselves uploading or use Vevo to curate their material.

It used to be MTV being music videos but as eyeballs went to smartphones and Youtube, and leaving even CATV behind, they're forced to rework their strategy by introducing non-MV content, like those reality-TV crapola, which only managed to repel the target audience, and partly contributed to MTV's slow decline.

Source: in two decades been watching youth transition from watching TV to PC to social media and Youtube to phones, and now this generation is largely glued to the phone.