I don't buy the "plants are green because they evolved in an era where certain spectral absorption ranges were used by a competing organism".
Sunlight isn't air or food. It's an unlimited source. Reflection or refraction of a reduced range of light (after absorption of a certain range) would play a minimal role compared to the abundance of light from above.
If it was a perfect system plants would be black with a level of transparency that decreases with foliage height (of the same genus).
And who is to say evolution has ended and what plants will look like in another 2 billion years.
