If we want to link the price of alts to bitcoin yes it is linked but why,
Practicaly:
Normaly as trader i monitor bitcoin price, if it is going to dump i sell alts and i turn to fiat, so this process will cuase alts dump and vise versa happen when bitcoin go up i buy bitcoin and start buying alts.

Logic , alts price is not linked to bitcoin but becouse of the process of caching usdt before bitcoin dupm that couse alts price to dump. But not all.