@miriamson
See Meged Givos Olam (vol. 1, p. 96) where Rav Shurkin writes that he heard that the reason why Rav Moshe zt’l did not want to write this teshuvah permitting shaving machines in Igros Moshe is because while (according to the Igros Moshe) it is technically permitted to shave, the tzurah of a Yid is with a beard. Rav Belsky zt’l stated the same.
You still haven’t answered why all pre war bochrim seemed to be clean shaven
As attested to by countless pictures