You have a list, from the internet, of those who have been said to have achieved Nirvana. Have my doubts about any such list being extensive or accurate to a large degree. Aliester Crowley, a metaphysician, wrote once that it would take almost a fool to have achieved enlightenment and then try to provide it for others. More likely there are many who did so, looked at their fellow humanity, and just continued to live their lives in peace, doing what they could, while not drawing attention to themselves. There are some few, who reaching such a height, could not hold back from trying to be helpful to others, Crowley does snot have a high opinion of such, for it is a fool's errand.
Buddhism at its best, shows one a way forward. It is up to the individual to see for themselves if in practicing it, they find any benefit from it. If so, it is worth following it, as my dad used to say, "Stay with a winner, till its a loser."
If Nirvana was meant to be a blissed out state, where one did nothing to help others, just float along peacefully, why would the Buddha have set forth on the way of the four noble truths and the eight fold path?
If you applied the same standard to Christianity, considering the paucity of saints, would that be a reason from dropping it?
Buddhism states and teaches one has to begin somewhere, doing something, to heal both one's self or mind and the world. From there it flows forth, providing the path for you to attain what you will.
Alan Watts was cool, but who says we all have to embody everything that a given philosophy or religion attests to? We are human not gods, saints, or enlightened beings. Go peaceably on your path, do what you can, and you may find it far more than anything you ever thought was possible.