I think this is a barbers (wives) tale that came about from barbers shaving 20 to 30 guys a day using the same edge. I don't think it applies to the average user. Sounds like it might have been a good advertisement ploy back in the day though.
Shaving one face, with one razor, has worked daily for me for years. I even stopped rotating razors completely about 2 years ago.
Hold the phone here!
You use only a single razor? All the time? Year in, year out?
May I inquire as too what razor you have settled on as your workhorse, just because I'm curious?