Well there is no suprise about this, the cryptocurrency market is all centered around the big one, every one is working to get bitcoin because in people's eyes bitcoin is the only successfull coin, poeple only started to use altcoins just when mining bitcoin started becoming more and more difficult, so mining other altcoin with a less difficulty than bitcoin with a much lower coast machines is much profitable than dierectly mining bitcoin, and of course they do all this just to be able to exchange it to bitcoin so they can get even more profit, because everyone knows that altcoins are very unpredictibale and could crash at any time because they have a much smaller user base than bitcoin.