I remember reading from “What The Buddha Taught” (Walpola Rahula) where the Buddha told Ananda that he did not have public teachings on the one hand and secret teachings on the other; that there is nothing witheld in “the closed fist of the teacher”.
For a number of years in the past, I’ve had my share of exposure to the “faster way to salvation” (mostly Mahāyāna), and sudden enlightenment (mostly Zen). More esoteric schools then evolved from Mahayaha, where there are public and private teachings (Tantra, Vajrayana, etc.). They are very alluring to certain types of people; and summbodhi’s analogy to MLM, although crude, is apt here.
Anyhow, we are very lucky to have ended up here instead.