The king of all the crypto currency is influenced by the bitcoin market. Bitcoin influences the price of another currency on it. Bitcoin prices are discussed more in the market. The more markets will be discussed, the more it will get market expansion.
Maybe we should just put it this way, bitcoin is the first, highly used, more established and more traded in the biggest level than any other cryptocurrency and that gives it an upper hand in the market. Also, we need to understand that most altcoins are tagged in price as well with bitcoin and as a result of that, we also get to see most traders considering the altcoins as money making market and that in itself makes the fluctuation in price of bitcoin to affect them greatly.
investors would rely more on the future of bitcoin and only use altcoins as stocks in the long run, which is what I believe will end up happening in this market.
You mean people will sell off their altcoin stash whereas they will keep holding their bitcoins ? Probabaly if bitcoin gets more number of real life applications then we cannot expect people to sell and book profits unlike they usually do with stocks.