I was wondering about the PHD for Master Pierro myself. I have much respect for all masters and professors I have met and trained with/under, but it's really just an Americanized title. I have many friends who train in different systems and the only "Master" is the head of the system, and he passes that title on before he passes away. In our SKK system, 5th degree earns us the rank of master, but my friends who are 5th or higher in other systems still refer to themselves as sensei or sifu. It all depends on what system you study. And then you have the "McDojo" masters and grandmasters who use titles for monetary gain to impress existing and would be students.
Respectfully,
Andy Henson (sandan)
Lynchburg, VA