What most people forget is that MTV, along with all other TV channels, Radio stations, magazines, news papers, belongs to the mass media industry and so, their first role is to make money. They don't care what they are showing as long as they make profits. And what better way to make profits than to show kids what they like. They could play music and forget about all the shows but then their ratings will drop and the money pile will dwindle in size.
On a side note, the reason you see so many reality shows on MTV is that the reality show format is the most popular tv show. Just look at what Big Brother did.
On a side note, the reason you see so many reality shows on MTV is that the reality show format is the most popular tv show. Just look at what Big Brother did.