That's one thing I don't like about the big coins. They have become correlated. They tend to move up and down together, like stocks.
True, it seems that the prices of ETH and LTC is dependent on the price of BTC these past few months. When there was a dump on BTC price the other two alt coins dropped value while XMR price skyrocketed. Now BTC price is moving to an upward trend hopefully ETH and LTC will follow.
This is evidence that bigger players are more involved in crypto trading, which is good and bad. One of these I dislike the most is the correlation with stocks to the indexes.