Many well known spiritual teachers talk about 'self enquiry' as being the most direct way to enlightenment.
They say; explore the question 'who gets enlightened?', or in meditation ask yourself 'who am I?' Its a riddle, designed to take us inward. If we really do try this and persevere with it, eventually the discovery is that we cannot find the answer in the sense of a tangible, definable object - and of course - that is the answer!
Under examination, our self, or at least what we had believed our self to be, is impossible to pin down because it has no physical location we can identify, it is in a constant state of change, and all aspects of it are temporary. The more we look, the less solid it becomes, and eventually we discover we are not our bodies, emotions or the content of our mind - we are more like a 'stillness, or presence' that sits behind - and this is not a separate entity at all. The truth becomes evident - we are beyond form, we are conscious but we are not just our thinking and feeling self.
Consciousness seems to be the essence of everything and apparently when it comes into being as a human, it gets temporarily lost in the body and the mind and starts to have thoughts that it is an individual 'human being'. This seems to be just a stage in evolution and eventually ultimately consciousness is destined to emerge out of the density of form and recognise that it was temporarily lost. When this happens the human being becomes 'enlightened to that reality', and this is a permanent experience of reestablished unity with what various traditions call Source, the Absolute, Self, God, Brahman, or just simply Consciousness.
Consciousness then is the ultimate reality, and we, as expressions of it, only have a 'quality' of reality that seems like it is all there is - until we experience the revelation that there is something deeper and permanent - that we are just playing our part in the evolution of all existence.
My sense of this is that enlightenment is always there, revealed when the association to the mind dissolves completely and we come back to the knowledge that there is no separate self and never was.