A Vision of the Abundant Universe
I think we can find the answer in a book written by Henry Thomas Hamblin titled Within You Is the Power (go through the link for a free download of this foundational work) gutenberg.org. In his book he states that the personal reality is largely a matter of thought, image and emotion. The higher the quality of these elements, the more "happiness" is achieved by the individual.
This sounds a lot like the Seth material, don't you think? So yes, I agree, we create our own realities and even though it appears that the average citizen is being dominated by the naysayers, slowly, relentlessly the Light Workers are creating positive collective power in the world. And we do that by modeling for others the right way to live: with every action for the highest good.
Effectively, that means we absorb everything, including the negative realities, including the environmental atrocities and the injustices against us, and send it back out as Love. With Loving Understanding and Courage to guide us, we forge ahead towards that Tipping Point that Seth talks about in his books. The Positive Manifestation is within our grasp.