⭐ Merited by pooya87 (2)
Due to its pioneer status, a lot of investors views it as the crypto market reserved so another coins depend on its value to remain high. So Bitcoin is a leading cryptocurrency at the digital crypto market.
Being a pioneer is not important. In fact Bitcoin is not a first cryptocurrency but it is a first successful one.
If they want to manipulate this market, they pull their triggers with Bitcoin first.
In Bitcoin pumps/ dumps and altcoin price actions (2013 - 2020), you can get some data for reactions of altcoins with Bitcoin rises and decreases.
Coin360.com is a good website to observe these reactions real-time.