This is thb main point missed by many of these teachers, lack of support for the hours and hours on the cushion required to develop the mind sufficiently to be able to begin to see reality at it is, clear from distortion and break through to liberating insight.
Upaññāta Sutta - The Known
“Bhikkhus, I have personally known two things: non-contentment in regard to wholesome qualities and indefatigability in striving. I strove indefatigably, resolved: ‘Willingly, let only my skin, sinews, and bones remain, and let the flesh and blood dry up in my body, but I will not relax my energy so long as I have not attained what can be attained by manly strength, energy, and exertion.’ It was by heedfulness that I achieved enlightenment, bhikkhus; it was by heedfulness that I achieved the unsurpassed security from bondage.
“If, bhikkhus, you too would strive indefatigably, resolved: ‘Willingly, let only my skin, sinews, and bones remain, and let the flesh and blood dry up in my body, but I will not relax my energy so long as I have not attained what can be attained by manly strength, energy, and exertion,’ you too will, in no long time, realize for yourselves with direct knowledge, in this very life, that unsurpassed consummation of the spiritual life for the sake of which clansmen rightly go forth from the household life into homelessness, and having entered upon it, you will dwell in it.
“Therefore, bhikkhus, you should train yourselves thus: ‘We will strive indefatigably, resolved: “Willingly, let only my skin, sinews, and bones remain, and let the flesh and blood dry up in my body, but I will not relax my energy so long as I have not attained what can be attained by manly strength, energy, and exertion.”’ It is in such a way that you should train yourselves.”
(AN. i. 50)