CIE 2006 model presents a convenient framework for calculating the cone fundamentals, and thus the color matching functions, for various ages of an average observer. CIE 2006 model incorporates three major physiological factors affecting observer variability, namely optical densities for the ocular media absorption, macular pigment absorption, and visual pigments in the outer segments of the photoreceptors. However, it does not have a provision for a peak-wavelength shift in the photopigment absorption spectra, a significant but difficult-to-model contributor to observer variability. In the context of color reproduction with modern emissive displays based on different technologies, we performed a theoretical analysis of various aspects of CIE 2006. Out of the above four factors, L-cone peak-wavelength shift was found to be the second most significant contributor to observer variability, after ocular media absorption. Excluding this factor from the CIE 2006 model, while understandable, can undermine the usefulness of age-dependent observer color matching functions.