It is certain that the price of all coins moves on the price of Bitcoin.
I am sure that in the near future, the stock markets will depend on/go away from the BTC price.
Because Bitcoin carries and will carry the only real and authentic value.
That time maybe Satoshi's value will skyrocket.
All of these are just transfer of wealth. And if you understand the trend you will understand it better. In layman's term, let's say you invested originally on Bitcoin, with it's dominance because of the demand, most investors would put their money on BTC instead of ALTCOIN. BTC HIGHER- BTC DOMINANCE HIGHER HIGHER
Then once you take profits on BTC, of course you sell your positions and buy more altcoins because now the opportunities for pump is in there. That means if you and more investors sell BTC, BTC will go LOWER- ALTCOIN will go HIGHER. After all it's just a marketplace and transfer of wealth.