Isn't Buddha normally depicted as being surrounded by datura flowers on his death bed? They might not have needed these things on any given day, but given that it's a path, you might need various tools from time to time to get around obstacles blocking the way. You might only use a substance once or twice in your life, but if not for that you might never have advanced any further.
If we take the sutras attributed to the Buddha as coming from one being, it would be laughable to think that this utter non-person would require anything to alter an already complete experience.
Repeating myself, but the same goes for the great mystics past & present. As to what they did prior to awakening, perhaps some did take hallucinogens, but given that none of the extant teachings suggest ingesting external substances, we can conclude that hallucinogens are non-essential to awakening.
In the west, where materialism reigns, many of us grow up spiritually bankrupt and turn to strong experience (hallucinogenic intake in my case) as a means to fill the void. Provides a much needed break from technology and rational thinking, but not convinced that this does much more than spin the wheels in place.
