So, add another study to the evidence that legalization may reduce wine sales: Helping Settle the Marijuana and Alcohol Debate: Evidence from Scanner Data.
This study claims that medical marijuana legalization reduced alcohol consumption by about 15% in the affected states. We should pay attention to this. It reinforces Tom Wark's opinion that we should not look upon marijuana as a natural marketing ally of wine - something I wholeheartedly agree with. But, let me also throw out a few caveats:
1) Though the researchers did perform some quality robustness studies, they also relied upon Nielsen data, which captures only 40% of wine sales. The Nielsen sample is also not representative. It does not include independent bottle shops, Costco or Total Wine. This leaves open the narrow possibility that these trends are actually just moves away from Nielsen-tracked channels. For instance, the trend could be driven by Costco's corporate strategy. Or, it may be that people are drinking less, but better wine: Nielsen-tracked channels tend to have lower average bottle prices.
2) The study looked at alcohol overall. It may be that marijuana is substituting for liquor or beer, but not wine.
3) In states where cannabis prohibition has been ended, medical marijuana and illegal marijuana have been easily accessible for a long time. It may be that medical legalization harms wine, but full legalization produces no or little discernible harm on top of this.
4) Finally, when one takes a basic look at the data, it seems that cannabis and wine use are correlated geographically and temporally. In states where people use more cannabis, they drink more wine. In periods when cannabis use has risen, so has wine consumption. The two blog posts below lay out the data:
Will Marijuana Legalization Reduce Wine Consumption?
More People are Using Cannabis - Are Fewer People Drinking Wine?