It certainly is more potent today, because the stuff you buy at a dispensary is not “ditch weed” grown in open fields for mass production anymore, it is hybridized and selectively bred for potency, and grown in conditions meant to maximize both yield per individual plant and potency.
But the other side of that is, back when everyone bought “ditch weed”, it was much cheaper, and people would just smoke mass quantities of it until they got high. Now you can take just one or two hits and have the same effect that smoking two or three joints used to achieve. So most people are naturally going to consume less than they would before, because they just don’t need to in order to achieve the desired affect. That’s not true for everyone, of course, because some idiots will just keep smoking until their brains are totally fried. But for most people, that’s probably not their aim.
not everyone smokes weed, a lot of people enjoy edibles which have higher potency