What is it with the old age

We come to life in a pure form, we don't hate anyone, probably don't love anyone. We are physically dependent on others, etc. I think we go through a circle, we get to know our surroundings, train our brain, and get into system. We learn all worldly things, attach ourselves to people and things, that might really not matter beyond this life, or even for this life if we can believe so.

When time comes, we probably start preparing for our departure from this world, lot of us slowly get to the state we came to the world. We start getting dependent on others physically, lot of worldly things stop bothering us, we stop caring for career, money, etc. We stop caring for what others say and think about us, slowly we start getting indifferent to even the people around us whom we considered closest.

There are few things about this old age that came to my mind, they are not necessarily right or wrong, but they are just thoughts. Everyone loves infants, we literally take care of them the whole day, clean their shit, feed them, etc., but we don't take that good care of old people in the same state. Why is that? Why do we even see the difference in our love towards the two?

What is the reason that we go through this cycle? Do we really have to learn something from this? When we get old, do we really understand this or we don't understand this and just live it out? If we know that we are going to go through this cycle, why the hell are we attached to all the materialistic matters?

If people do not understand the purpose of their life even when they get older, then why do they attempt so much to live as long as possible even after the fact (which they know) that their life is almost over, and adding couple of more years is really not going to make anything better but just increase suffering?

Some authors in some of the books opined that we cannot live this world until we have done the learning we were supposed to do here in this life and are not ready to go back with our lessons. We might be undecisive about this and might go to intermediate states (like Comma), but still can't live the world. Is this really true? If so, we really know why we are here and what we need to get from this life, but it's just how to sync our physical and non-physical selves... Is it just that???