Bitcoin's dominace is increasing these days, and ethereum is also rising up, but it doesn't means that alt coins are dying. With the segwit2x coming this Novemeber a lot of investors are buying bitcoins, but don't be anxious. After the last fork happenend the price of alt coins recovered in a few weeks. So if you have a lot of money invested in alt coins, wait and see and remember that you only loose money if you sell in red. Alt coins is a market and like just any market there is a degree of volatility, but I do not think that the market is going to collapse.