The color of every photo on the internet blended together is orange

the plants consume edges of spectrum, so they would bounce the X wavelengths (green in case of our Earth) as it is just an unnecessary heat for them.

There's no real consensus on why. (There's some wild guessing that green photons might be too hot to handle: smashing fragile biomolecules apart rather than powering them... (http://scienceline.ucsb.edu/getkey.php?key=500) but then why does chlorophyll run fine on purple light?) You'd figure that there would be incredible selection pressure on increasing photosynthesis efficiency, but maybe they're stuck on a local maxima: it's not like a single mutation can turn a C3 plant into a C4 plant: http://en.wikipedia.org/wiki/C4_photosynthesis

The same phenomenon happens in audio. The vast majority of musical synthesizers either model the perception of sound or the physical production of sound. For example, you can model a piano as a physical system with a vibrating string, or you can model it as a subjective phenomenon, constructing a frequency spectrum that sounds similar using FM synthesis, subtractive synthesis, additive synthesis, et cetera--none of which correspond in any meaningful way to the piano itself, we're really trying to trick the ear.

In the same way, I see RGB as a simplified physical model rather than a perceptual model, because it does correspond rather closely to physical reality, and it corresponds somewhat poorly to subjective reality. You can construct RGB as a simplification from a continuous spectrum model of radiation, all you have to pick the spectrum of your primaries. From there, you can use the RGB model in your physical simulations, such as ray tracing and photon mapping. Lab color does not work well for ray tracers because it does not correspond to physical reality: it is fairly nonlinear, and the coordinate system is awkward.

Likewise, RGB is a poor model for subjective perception (compared to Lab or XYZ) because its gamut is limited, and differences in RGB space do not correspond well to differences in subjective qualities. You can see how awkward RGB is for perceptual modeling whenever you use a color picker. It is frustrating to try and construct a pleasing palette of colors by dragging around RGB sliders, or even HSV/HSL sliders, because the model is so far from subjective perception that doing something conceptually straightforward, such as altering hue or matching luminosity, requires fiddling about.

In short, the description of RGB as a "physical model" is because we use it for physical simulations, as well as for working with hardware such as monitors and cameras. My description of Lab, CIECAM, XYZ, etc. as perceptial models are because we use those for modeling the subjective perception of color.

However, when you say "pure white light"... there is no such thing! White light is a combination of different wavelengths of light. You can indeed make light that looks white (and therefore is white) by combining monochromatic yellow and monochromatic blue light sources. Amazing! Even though it will look white, objects illuminated by this unnatural light source will have unexpected colors. This is quantified by the CRI of a light source. Incandescent lights are defined to have a CRI of 100, but this is just a convention: the blackbody spectrum is quite common. If you grew up under fluorescent lamps, colors under the light of day might seem quite unusual.