This was easy to predict.
Anyone who's been in the industry knows that there is not only not enough demand, but it is also seasonal. Other than the heaviest users, people don't consume 365 days out of the year, they go through phases.
If you grow weed year round in high tech facilities that maximize production, you're going to just have massive piles of it that you cannot unload.
Making it legal didn't really create that much more demand because it was already easy enough to get in most places where there were enough consumers.
I drove through Oregon not too long ago. There is literally miles of weed shops right next door to each other. There are more weed shops than gas stations... and the gas stations usually have one right next door anyway. I have no idea how they all stay in business, but it couldn't be good.
Now this is the comparison to tulip mania that kind of works.