Bitcoin is the King of cryptocurrency market because

It is a first successful cryptocurrency.
It is a pioneer for Blockchain technology.
It is a cryptocurrency with biggest marketcap and biggest daily trading volume.
It is a most popular and most accepted cryptocurrency globally, on exchanges and in many platforms.

If Bitcoin hiccups, altcoins will be in bloodbath. In a day or two days, you will see the market reacts with Bitcoin hiccups.
https://coin360.com/