Ronald Fisher and Karl Pearson the Grandfathers of Six Sigma !

Why are Ronald Fisher and Karl Pearson not celebrated and discussed more in Six Sigma forums and in Lean Six Sigma training courses the same way as the likes of Shewhart, Deming and Juran ?  ( I am already telling my students about them !)  Could it be because Fisher and Pearson's main focus was not on Industrial Manufacturing and Business ?   Nevertheless, many of the statistics used today in Six Sigma tools and techniques ( Correlation, Regresssion, DOE , Capability Analysis etc ) are based on the work of either Ronald Fisher or Karl Pearson.  If Walter Shewhart is the Father of Statistical Process Control, then surely Fisher and Pearson are the Grandfathers !