Earlier quoted context omitted.
Hasn’t really happened in Canada. I think a small-player alcohol company did move in, but only after the bubble popped. Turns out legalization of a drug doesn’t lead to massive increases in consumption. Who knew. Definitely kneecapped the black market though: most moved to the legal side and black market prices cratered.
Marijuana use has massively increased in the US as states have legalized it. Users have doubled: https://www.statista.com/statistics/264862/cannabis-consumpt... Use among users has also increased 20%: https://www.eurekalert.org/news-releases/962353
Same happened after alcohol prohibition: more people consumed after the ban was lifted, but consumption was safer. But rarely people that didn't consume during the prohibition went on alcohol binge after the end of the ban. They just drank a couple of beers per week, maybe even a glass of bourbon twice a year, now that they can buy and consume it safely.
Thus the stats you linked doesn't necesarily show a "massive" increase in use, but many people using it sparsely now and many people now admiting to use it that were using previously. In fact, while statista.com shows a 100% increase, the second and more controlled study shows only a ~20% increase that makes more sense (far from massive).