I don't think altcoins can survive without btc, so I think the price of btc will continue to affect the price of altcoins.
some examples have been seen when an altcoin is rising, then the btc price suddenly drops, the altcoin will also immediately fall.
Altcoin/bitcoin has undergone a lot of change in the past few years that we must take into account
1. We have more decentralised exchanges with different blockchains where bitcoin can not be traded and they still make large trades
2. That the decline in bitcoin-altcoin has decreased and we have more stable-altcoin and altcoin-altcoin
3. That bitcoin have less than 45% market dominance, less than in previous years and approaching halving.