Astus wrote:"You can gather from what I've told you that my practice lasted many long years and that I came to realize my Buddha-mind only after great hardship. But you can grasp your Buddha-minds very easily, right where you sit, without that long, punishing practice. That shows the relation that links you to Buddhahood is stronger than mine was. You're all very fortunate indeed."
Easy to grasp is not easy to manifest. Manifestation, in my mind, involves things like purifying the patterns of energy that make up the mind-body. Grasping the unborn won't necessarily free one of the knots of the muscular body or the vasanas/samskaras of the mind. I like how it is put by Chinul in Secrets of Cultivating the Mind (quoting Kuei-Feng):
Although we know that a frozen pond is entirely water, the sun’s heat is necessary to melt it. Although we awaken to the fact that an ordinary man is Buddha, the power of dharma is necessary to make it permeate our cultivation. When that pond has melted, the water flows freely and can be used for irrigation and cleaning. When falsity is extinguished, the mind will be numinous and dynamic and then its function of penetrating brightness will manifest.
This teaching is very prevalent in non-duality circles outside of Buddhism --- perhaps because it appeals to the demand for instant solutions. Yet, even the stars of non-dual teachings, such as Adyashanti, Papaji, Nisargadatta, and so on went through periods of often intensive practice. Even Ramana Maharshi, who was said to be instantly enlightened at a young age, actually followed his early realization with years of intensive silent practice.