I'm surprised nobody has posted what the real deal is. They're changing the platform, but no videos are going to be removed. The media didn't understand the initial information and ran with it.
What will happen is YouTube will behave more like a streaming music service when it comes to music and monetization will be different. If you want to monetize music on the new platform, you have to register your videos as music so they can be properly monetized. If you don't, they won't be removed from Youtube, just not monetized through the music service correctly.
All in all, it will probably actually be good for artists. Separating music into a music only service will make things more user friendly and undoubtedly increase the actual amount of music consumed. Music specific monetization will probably earn more too, so you're going to get more plays as well as higher earnings for every play.
Just try to think about it as a Youtube vs. Soundcloud thing. Soundcloud is obviously better for consuming music, but Youtube has a much much bigger market share with the power of Google behind them for actually making artists money from free plays. Take the functionality of Soundcloud, apply it with the market share of Youtube and that's probably what you're getting.