Is Reincarnation inevitable?

Assuming the universe is infinite, why are there beings that haven't spiritually evolved to the level of enlightenment? We've heard of Buddhists or people who've had Near Death Experiences that claim they have experienced non-duality, or the clear Light. However, this article seems to imply that we can only experience "god head" when we have a physical body to come back into to give us reference. Interesting read for anybody interested in NDEs and/or The Tibetan Book of the Dead.

[link to renejorgensen.com]

So, is it possible to attain enlightenment and stay in that state eternally, or will you always be sent back into a form only partially aware of the whole source in order for the source to know itself?

Opinions.