I'm not sure you should discount the spiritual potentials of alcohol, as Plato is supposed to have said “He was a wise man who invented beer.”. In both Christianity and Sufi Islam wine has a long and important spiritual symbolism.
Cupbearer, it is morning, fill my cup with wine.
Make haste, the heavenly sphere knows no delay.
Before this transient world is ruined and destroyed,
ruin me with a beaker of rose-tinted wine.
The sun of the wine dawns in the east of the goblet.
Pursue life's pleasure, abandon dreams,
and the day when the wheel makes pitchers of my clay,
take care to fill my skull with wine!
We are not men for piety, penance and preaching
but rather give us a sermon in praise of a cup of clear wine.
Wine-worship is a noble task, O Hafiz;
rise and advance firmly to your noble task.
While I agree that cannabis and certain other substances may be spiritually uplifting, and cannabis can also certainly be similar to alcohol in its social and cultural usages as well, I don't think most idiot Westerners who use these substances do so with any spiritual benefit though, beyond sometimes indirectly through the social and cultural effects. Spiritual development takes effort, it takes preparation and it takes purification. This is why shaman who use entheogens do so in a meaningful ritual. College kids who ingest magic mushrooms do not. It at least takes some grounding in a spiritual tradition and enough of a spiritually qualified mindset.