Almost all Golden Age courses were designed and built before the advent of the sand wedge. Perceptions of how one played out of bunkers changed dramatically after Sarazan's invention.
My guess is that Tillie, Wilson, Ross, the whole lot of them, believed bunkers to be much harder to recover from than anyone does today. Bunker shots were perceived as a very risky business. Even for the best players. We tend to forget that.
To get to Tom's larger question, yes, bunkers back then (whether or not trampled by elephants) were truly terrifying and, therefore, effective shapers of strategy.
For modern architects the conclusion would seem to be that (a) bunkers in the Golden Age played much, much more difficultly than they do now, and (b) modern bunkers, if you want them to have the same strategic teeth, must be rethought for them to have the same fear factor today. The sand wedge and modern bunker maintenance practices changed the equation. A bunker in 2004 doesn't frighten anyone the way that same bunker would have in 1924.
Bob
P.S. There is lots of talk about how titanium heads and graphite shafts have revolutionized the game. But the advent of the sand wedge was no less revolutionary. It had a permanent and profound impact on gca that is rarely noted.