What is this quote from? It strikes me as quite familiar.
I would venture to include that, as demonstrated in the variations by which they are visualized, the chakras are not necessarily fixed and specific necessity but intensely useful visualization techniques utilized in the understanding of the flow of energy in and around us. They essentially translate these specific flows to us in a manner that lets us very clearly understand the nature of this energy - it is for this reason that they endure within spiritual practice, and have proliferated not just their Hindu origins but a sweeping range of Western and Asian traditions as well. Some may argue that in seeing them astrally, or otherwise achieving results through direct work with them, the Chakras are absolute - not manifest visualization but un-malleable truth.
I would counter that all experiences of the spirit are represented to us in the manner that provides for us the clearest understanding possible, and that perception shall always vary between individuals to some extent. If not exploring chakras, then from what would we call this energy? An aura, perhaps. Or a halo. Visualize lotus flowers, energy vortexes, or anything at all, fluffy bunnies, rainbows, stars, moons, or anything at all that may work for you. Visualize them externally, outside of yourself. Now attribute to them the same qualities and impact as each of the seven chakras, and your meditations and energy techniques will have the same result.
Insofar as the kundalini, there is a great deal of interpretation and literature upon this matter. Many see it as helping one to ground, or otherwise being the the awakening of the self. Thus as kundalini rises, as traditionally described, it ascends through the chakra... bringing the self into awareness of these energies associated with each chakra in turn, as the above text describes as the kundalini interacting with the lotus flowers, and turning them right side up.
This, in my opinion, is merely a metaphor for awareness. As we grow aware, the chakras open and expand on their own. This can be achieved through exploration of individual chakras... or the energies associated with them, or through any number of other methods of magical exploration that bring us into a heightened state of awareness.
Thus, as we become aware of the energies of the universe and can sense them, one might say that our third eye begins to open... though before we may not have been aware at all of the chakras, or even the concept of a "third eye chakra."
Just a bit of rambling. Hope it made sense.