There seems also to be a difference of opinion what R Chisda means by “shok” in Berachot 24:
Hazon Ish thinks it is a lower part of the leg, Mishna Berurah and Moshe Feinstein – upper.
Hazon Ish reasoning – nobody in their wildest dreams (pardon the pun) would walk with revealed upper leg, so R Chisda obviously means “lower”. This is, obviously, cultural, and R Feinstein had different environment starting w/ 1960s … Not sure about Radin.
Do we know what was typical hem line in 3rd century Bavel? That would resolve the shok machlokes.
PS economists claim that the length of the hemline is inversely proportion to GDP growth rate ..