The reason Buddhist teachings are often in the form of numbered lists is because at the time of the Buddha things weren't written down. The Buddha and the monks couldn't read or write, so they memorised the teachings. Making them into numbered lists made them easier for memory and recall. Then on their own, a person would contemplate and reflect on their meaning, unpack them, investigate them, fill in the details through their own practise and experience of life.
The reason we can't go straight to the deathless, why we need to study and practise, is because the concept of letting go is easy enough to see intellectually, but we are all conditioned and have formed habits that get in the way and make it hard to let go. That's why one must undergo training to decondition the conditioning. Then old habits gradually fall away, and new ones develop that help us to realise the state of non-clinging, or non-attachment. The end of suffering.
The intellectual thinking part is also important as it helps us understand where we are going and what the teachings are for, why we are practising and what the practise is leading towards. Another translation of right view is right understanding.
But it is a gradual process. Which involves making the five aggregates into a path, the noble eightfold path. The robe of liberation. The Buddha likened the path to the continental shelf of India, that gradually slopes down, and eventually reaches a point where it suddenly drops off into the abyss. That's what the path does, it gradually leads us in the direction of nibbana (the end of suffering). And when the path factors are sufficiently developed, there comes the sudden insight, the Eureka moment, were we see something we cannot unsee - that's the drop-off point, enlightenment. From there, there's no going back, one will never see things the same way again.
It doesn't mean one is separate from the world though, it just means one stops clinging to it, stops yearning for things. The pain of wanting is gone. Craving is extinguished. Conceit is seen through, and the involuntary movements of the mind cease - which brings profound relief. A peace and happiness not dependent on conditions, independent of the world. And because it is not dependent on conditions, it lasts, and doesn't end.
But love and compassion for other beings is still
there. Friendship and connection are still there. That doesn't go. If anything,
it grows. Loving-kindness becomes unlimited, immeasurable, abundant.
Without the ego placing limitations on it, one's compassion becomes boundless.
The whole process is illustrated nicely in the ten Ox-herding pictures in Zen.