Just to clarify a little bit about what has changed from a routing perspective from the course that opened in 1912.
Holes that changed completely are the old 1, 10, 11, 12, 13.
Green sites were moved on 2, 8, 14, and 17 was completely rebuilt by 1916.
Also, as noted, most of the bunkering wasn't done when the course opened, which is completely incongruous with the Macdonald style when you consider that virtually every one of the template holes are self-defined by their bunkering strategies.
Merion repeated none of them. The supposed redan hole does not have the standard redan bunkering and we know the green is the opposite of the redan style. "Far and Sure" said the supposed "Eden" greeen on 15 didn't work at all, and we've seen that the supposed "Alps" hole on 10 was not blind, nor much of a good hole.
I'm sure the Committee wanted to create some of the famous holes...it was the rage Macdonald started. I'm sure it just became sort of a useless exercise when they realized they could create some of the same type of challenges and strategies while creating something a bit more original.
Trying to do otherwise would have required mass changing of the landforms, and I'm sure they quickly saw the futility in that.