Ease of manufacturing is also a major factor. All you need is sugar, water, yeast (which can come from a multitude of sources), and patience.
With cannabis, all you need is... cannabis. No patience required.
Sugar, historically, has not been available or even cheap.
Sugars are commonplace. If you can make bread, you can make beer.
Making alcohol by fermenting fruits is comparatively much easier, but then again, cultivating and harvesting fruits is a pretty laborious process.
Then actually brewing beer is not that simple.
Even today, with availability of source materials and technology, homebrewing is a rather involved hobby. Same with producing wine that's drinkable.
On the other side, we have literally a weed that needs very little to grow, and requires nearly zero processing.
I really see no comparison here.
The theory that we started making alcohol for food safety/nutrition reasons makes the most sense to me.
There's even some evidence, perhaps of questionable quality, but it makes a good story at least, that we may have evolved to prefer alcohol despite its toxicity because it was a reliable source of safe drinking water.
And even newer theories saying it may be related to the smell of ripe fruits leading to some primates getting a better source of energy.
In any case human affinity for alcohol likely goes back very far.