Bill Brightly,
I think the introduction of Bluegrass, which was a major trend for a while, needs to be reversed.
If you look at aerials from the 40's, 50's and 60's, many fairways were adjacent to the bunkers.
Many of the buffers of rough you mention were introduced subsequent to the installation of most irrigation systems, hence, I don't believe that "irrigation systems" are a major impediment to eliminating those buffers.
Like fast play, I believe it's a cultural resistance.