The Readiness and demand problem

From 14 years of age onwards, most science curricula demand the use of formal model, proportional and probabilistic reasoning. An example, as used in the previous dialogue about chemical reactions, is particle theory and all its applications in Physics, Chemistry and Biology. This theory is usually  introduced at grade 9 (14 years of age).  This theory demands all of the formal operations. However only the upper quartile of the population seem to be beginning to develop these formal operations.