when a sefer becomes a personal name, should we use it correctly? Maybe, when the naming happened during their lifetime? There were no such people as Beis Yosef or Chafetz Chaim – only Beit Yosef and Chofetz Chaim …
It is amazing how well written Hebrew survived comparing with Oral (and with other languages). Maybe the point is that we can see how reliable written tradition is comparing with Oral. I may not be able to converse with someone from Munkach, whatever country it is, but I can read Rambam (in Hebrew translation)