...the [A∴A∴] system which was given to me to put forward is only one of many. “Above the Abyss” all these technical wrinkles are ironed out.
Crowley wrote that in chapter 9 of Magick Without Tears. Although the context of the statement was a discussion of the Secret Chiefs, the underlying admission is striking. Crowley seems to be saying here, in rather unambiguous language, that the A∴A∴ is not the only viable system for attainment in the New Aeon. In fact, he says there are "many".
He goes on to say in chapter 17:
I certainly have no intention of "holding you down" to "a narrow path of work" or any path. [...] It does not follow that a plan that I have found successful in my own case will be any use to you. [...] Most teachers, consciously or unconsciously, try to get others to follow in their steps. I might as well dress you up in my castoff clothing!
Again, not only is the A∴A∴ system not an absolute requirement for attaining to one's Will, but AC is saying that one would be wise not to "follow in his footsteps."
So, what is my point in all this? That ultimately, we must all follow our own unique paths to our True Will. Some will choose the strict A∴A∴ path, and that's just fine. But as Crowley tells us, there are many available systems...I go further by suggesting that there are as many "systems" as there are individuals, in the sense that every person's path to Will is unique. As AC said in "A Memorandum Regarding The Book of the Law"
Each of us has a Will of eternal import, necessarily related to everything that exists, and all our conscious desires are so many masks—one fixed expression concealing our infinite variety.
The Grades of A∴A∴ are an abstraction based upon an arbitrary model initiated by Mathers (leader of the Golden Dawn) and later developed by Crowley and George Cecil Jones, largely in relation to a power struggle over the concept of Secret Chiefs and their supposed ability to give spiritual authority. To me, that is all Victorian-era occult-culture gobbledygook. None of that is necessary to legitimize Thelema or to authorize a path of Thelemic attainment. The "New Aeon" is all about the individual and it follows that it is the individual who decides his proper path to Will. AC said as much on several occasions.
One of the major handicaps of Thelema, in my opinion, is how tightly bound up it is with the A∴A∴. Essentially, for many people, Thelema is the religion of A∴A∴, which can therefore only be understood and practiced within the scope of its teachings. But that seems deeply counterintuitive to the nature of the New Aeon, which is the age of freedom. Yet Thelemites are often expected to conform to the practices and beliefs of this one small and now-splintered organization. This contradiction has hobbled Thelema from growing into the robust catholic religion that it should be...remember, the Law is for all.
I utterly deny that the Law "comes from" the A∴A∴—rather, the Law simply is. The A∴A∴ is one organization designed to help people attain to a new formula of enlightenment. But as Crowley suggested above, it is not the only system available. Moreover, it makes all the post-AL "holy books" suspect as being generalizable beyond A∴A∴ work. After all, those documents were written strictly within the mode of that system...but how relevant are they to someone working a non-A∴A∴ system? I won't go so far as to say they are irrelevant...but I do suggest that it is worth questioning.
The goal of the Thelemite is simple—to attain to an awareness of Will and to manifest it in life. If we agree that there exists such a thing, why should it be true that only Crowley's system is the only one available to reach that goal? In fact, we hear in the above quote that Crowley himself recognized that other systems exist that can bring one into a state of Union between the Self and the All.
I have come to believe that how one goes about doing the Work is largely irrelevant (as long as it is effective...gum chewing might theoretically lead to attainment, but there are probably better methods). What matters the most is intent and diligence. Crowley teaches his system because it worked for him. But as he said, "It does not follow that a plan that I have found successful in my own case will be any use to you." There are many tools at one's disposal: prayer, ritual, yoga, Qabalah, tarot, dancing, music, art, immersion tanks, hypnosis, and on and on. There are many ways to bypass the conscious mind and make contact with our deeper Self, and so come to an ever-increasing understanding of Will. As long as one keeps this basic goal in mind and keeps at whatever methods are chosen, one will eventually find Success.