For the past 35 or 40 years, films have been developed pretty much the same way, to a gamma of 0.65 or a bit less. That was not the case with earlier films, which were different in design. I was looking up something in an old PLI I have, dating from the late 1940s with supplements up to the early 1950s, and I noted that the recommended development gamma for old, orthochromatic Verichrome was 0.9 in D-76. Similar gammas were recommended for other Kodak continuous tone products and also Ansco continuous tone materials. In fine grain developers like DK-20 or D-25, times were listed for gammas of 0.7 to 0.8. These developers apparently couldn't reach the higher contrasts. I suspect the different recommendations are the result of changes in the film structure.