The cause is Price... They have overpriced themselves right out of business. It is double over fair market price and folks are tired of being screwed by the industry price fixing.
In many states the liquor taxes are very high—on top of everything else.
https://taxfoundation.org/data/all/state/state-distilled-spirits-taxes-2024/
Yes, this is driving a lot of the decline. Just like rising cigarette prices cause many to quit.
People knew smoking was bad for them but hey kept doing it as long as they were affordable enough.