I've some inchoate thoughts around this topic, so let's just see where this goes.
Based on my own experience at different stages in my life as well as on observation of others, I would describe two types of self-absorption. The first is the unaware kind. This is where the person's orientation is basically outward, toward finding satisfaction outside him/herself. But s/he is unable to find it because the reason for the outward orientation in the first place is the deep belief that there is nothing of value inside. Thus, the only hope is that what is needed will come from somewhere else. That need for the sense of emptiness to be filled is self-absorbed because the person isn't really interested in others except to the extent that s/he sees hope that others might fill the emptiness. Usually this orientation is pretty unconscious although someone who is doing this and is scrupulously honest might eventually get a sense that it really isn't about any genuine interest in others. Such a realization might be the start of a genuine search for truth.
The other type of self-absorption is the one that arises as one starts on the path to awakening, or re-starts after a period of outward orientation. Suddenly, everything and everyone in the environment comes to take a back seat. One does the daily tasks and maybe has a few recreational pursuits but the meaning of life only comes from absorption in one's advancement on the path. This kind of self-absorption, unlike that above, arises from an inner orientation. It is the one that leads to freedom.