No. Lysimachos point is true for Europe, up until about mid 20th centurty when at least in North West Europe people start to gain “length parity” with antiquity, and in case of some peoples especially males start to outgrow their counterparts of yore. Which is to say that in the Netherlands and Sweden we are on average bigger barbarians than we used to be.

Those length drops Lysimachos talks about coincide with times traditionally celebrated as some kind of “golden” age of growth and prosperity: growth and prosperity for a few extracted from society at large by further increasing relative poverty of the poor.