One of the reasons why Sanatana Dharma becomes the most logical and realistic among religious ideologies is its basic belief in the Theory of Karma and Rebirths. It is almost impossible to rationalize the accidental nature of our births and the sufferings of children without these fundamental beliefs. Once we have established the rationale of rebirths, Moksha or Enlightenment or Realisation becomes a necessity to complete the belief structure. There must be some way out to end the repeated cycle of our rebirths based on our Karma. Moksha seems to be the only way out.
Now how do we achieve Moksha or Enlightenment or Self-Realisation? Our scriptures and Rishis have indicated multiple ways to achieve the same. The method we chose depends (or must depend) on our qualities and capacity. If you are weak in mental abilities, there is no point in choosing the Knowledge path. Similarly those who are good only in learning, Yoga and Meditation are hardly the ways to attain Moksha. But whatever be the path one has chosen, it is absolutely necessary to go through all the phases of a human life. Without this it is not possible to close your Sanchita (accumulated) Karma from past lives.
Human life has essentially four phases - Brahmacharya (student), Grihastha (householder), Vanaprastha (retired) and Sannyasa (renunciate). Every human accumulates Karma in all these phases of life. After each life is over, he or she is reborn with the Sanchita Karma from past lives. Moksha is attained when one can reach the Sanchita Karma of ZERO ie. Papa and Punya becomes equal. So the bottom line is that one cannot aim to achieve Moksha in the current life unless he or she is prepared to go through all phases of human life. If there are Sanchita Karma from Grihastha (householder) phase in the early lives, it is possible to compensate them only during a similar phase in this lifetime.
Hence, I am convinced that none of the unmarried (or those who have never taken care of their wife and children) sages could have attained Moksha in their latest life as we know it. They would have been born again and attained Moksha after completing Grihasthasramam in a later life. This concept must be crystal clear to every one who is trying to attain Moksha by shortcut methods. You must necessarily go through all the four phases of life (in the current parlance), to suffer and enjoy the experiences in each phase, in order to escape from the cycle of births and deaths. There is no easy way out.