The Path of Enlightenment is not for everyone. For one thing, it takes dedication, almost an obsession. The thought of enlightenment needs to always present in mind.
This is what Zen monks are doing with their Koans – they are ways to balance the mind in openness. Enlightenment, or Satori as it is known in Zen, reveals itself in a flash when one keeps the mind in equipoise.
But as many sages have pointed out, it is few who really fill their being with the necessary emptiness, and readiness. Even for ardent meditators.
As with most good teachings, this idea has its source in the Suttas:
Amid all phenomena, the thought of Nibbana shall be present with me, as a slayer with a drawn sword
AIII 309 (PTS Trans)
The mindfulness training we do is directed to this end. Mindfulness can be brought to every activity. After a while, you are not mindful of what you are doing … you remain mindful despite what you are doing.