When bitcoin rises, the altcoins keep the price and if when the bitcoin falls the altcoins fall even more. Why do altcoins usually follow bitcoin?
It is called correlation, whenever the BTC price goes down the whole market dumps. The humans keep connecting the market fluctuations, especially on top financial tools and draw some lines on charts to predict the future potential of the trend. If the trend is down, altcoins keep losing value % in the long term. In case of BTC price loses 20% value, expect min 30% less performance by altcoin traders who gonna dump it. Watch tradingview charts and let us know what you see if you can find correlations on charts.
We can't change the nature of the market. The influence of Bitcoin in the market makes it clear that whatever happens to its price, altcoins are also affected. Like now, BTC is surging up and altcoins do the same trend. We'd see the huge buying demand causes the uplift scenario, keeping the momentum for Bitcoin makes the market go bullish.