I think it has a lot to do with market volatility of the alt coins making everyone nervous and feeling as if there is too much manipulation going on. The other elephant in the room is what regulations may be coming down the pipe in the US and other places. These most certainly will affect the alt coins disproportionately to Bitcoin. The SEC in the US announced that they are investigating many ICOs. When findings come out chances are it will not be good for many of the alt coins.