In general, this is true. Due to the high level of capitalization, bitcoin dictates the direction of price movement for the rest of the cryptocurrencies. Some altcoins may not keep up with the price movement of bitcoin, some, for various reasons, may even act contrary to the price movement of bitcoin for a certain time, but in general, bitcoin still dominates the price ratio in the cryptocurrency market.
I don't think this will always be the case. The time will come when Bitcoin's price dominance will disappear after its market capitalization drops to the level of capitalization of other altcoins.