Why Altcoins are related to BTC? Is this tendency over?

First thing first. 5 years ago I made a mistake. When I approached this world and read about some projects, I didn’t choose bitcoin. I thought and I think it’s an obsolete blockchain. My mistake was that I couldn’t see it as a store of value.

For that reason I built a small long term portfolio with my internship’s earnings based on ETH, SOL, DOT mainly and 2 more ones. Obviously I’m not rich now. Observing the market during these years I have noticed that when BTC drops, all the altcoins do the same; and vice versa.

If we see ETH, SOL, DOT as blockchains more efficient than BTC one, why their prices are still related to BTC?