This is fascinating. My first instinct is to say that the peak of those curves are not as important as where they discriminate best/where they are most different from the other curves - which does seem to give a more clear red, green and blue. But I’m sure it’s not that simple when you take into account how the brain processes these signals.
Would it be possible to create a good color screen using subpixels emitting light at the peak sensitivity frequencies?
Blue is chosen to have as small wavelength as possible (S=small) and red is chosen to have as long wavelength as possible (L=long), while both being still in the visible spectrum with large enough response from S and L cones respectively.
Since M and L response profiles overlap anyway and just the ratio of the response changes, green is chosen to be as far away from the red, but still outside of the response curve of S cones that get stimulated by blue. This happens to be also around the peak sensitivity for the M cones.
The diagram is misleading because the spectral sensitivity curves are drawn using red, green, and blue colors on the chart. Read the wavelengths on the bottom--they do not roughly correspond to red, green, and blue. This is why they are named L, M, and S instead.
The peak sensitivities are closer to green, a different green, and violet.
> That is hardly a coincidence. Our perceived color space is vaguely triangular because we have vaguely three types of cone cells to detect color.
It's a poor approximation of a triangle. It's more paraboloid.
It would be a triangle if there were no overlap between the spectral sensitivity of different receptors. Since there is overlap between the green, other green, and purple receptors, the shape is not a triangle.