I think it was more of an editing/time limit problem. In his seminal work 'Triumph Of The Moon' he does make the distinctions between modern Wicca and traditional witchcraft etc. Wicca has its roots in traditional witchcraft, as well as other systems. Gardner would have no doubt studied Israel Regardie's writings re. the Golden Dawn rituals. I don't think it really matters really. Buddhism was a construct borne out of Vedanta. I think Gardner's intentions were entirely genuine, and as for the efficacy of magic ? Ronald Hutton himself is respectful and sympathetic these days as a result of his studies. I'm not getting into another game of semantic one upmanship, but I will say that yet again, the proof or not is down to personal experience.