Instead of the majority of people mindlessly consuming media and products without questioning the impact it's having on their minds, their future, the environment, other cultures, etc, they might pause to ponder these things.
Rather than accepting society as an immutable construct that they couldn't possibly influence in a positive way, people might choose to participate in challenging the status quo.
In lieu of othering demographics that they don't understand, people might realize that despite some minor cosmetic differences, we're all humans that have a pretty vivid subjective experience of pain.
The elite benefit from a complacent majority. I would even go so far as to say they rely on a complacent majority to maintain their position. You don't have to venture very far to read stories about people who experience tectonic shifts in their patterns of thought after taking psychs.
The current fully legalized and regulated substances just don't have that kind of effect. Alcohol just lowers your inhibitions and arguably makes you stupider.