I've been monitoring the market for a couple of months now. Most of the coin value rely on the price of Bitcoin. If the BTC price goes up, every altcoins will follow and if it will goes down, the price of every altcoins will goes down as well. But the question is, Bitcoin price/value is still going up but the price/value of every altcoins especially Ethereum goes down. How did this happen? Any logical or scientific basis to explain this. As of now, I am still confuse.

The altcoins price not really depends on bitcoin. When the ETH price dropping great, btc price is still above $6000.
i think the most plausible explanation is, because many holders change their portfolio from altcoins to bitcoin.
There is a high possibility that they sold their altcoins to buy more bitcoin.
You are right. Because bitcoin is more attractive and also a dream of many people. Maybe that is one reason to sell altcoins to move to bitcoin. The price of bitcoin is expensive, it will continue to be chased by many people to have bitcoin that has been believed to be the king of cryptocurrency. That's what happened and that makes sense in this mind.