Ed,
This is a subject near and dear to my heart, but, I view it a little differently.
I understand that the maintainance issues increase, exponentially, as you get closer to the bunker.
But, that's not my primary criticism.
What I really object to is the extension of the rough further and further away from the bunker, forming a "safety net" or "buffer".
I watched as the buffering rough went from a foot, to three feet to three yards and more.
This wasn't maintainance "creep" where conditions unintentionally and benignly change, these were intentional attempts, vis maintainance practices, to make the course "more fair".
It tends to be an American phenomenon, and seems more prevalent at Country Clubs than golf clubs.
But, you even see it a great clubs like GCGC.
Certainly, with sharp edged, deep bunkers, there can be safety issues associated with "riding" to close to the bunker.
Walking mowers would be the prefered method if cost wasn't an issue.
It can be done. It is done. The "road hole' bunker at # 7 at NGLA is probably a good example of successful execution/maintainance.
Tom Doak puts forth a valid point, turf or soil that can't withstand the traffic. But, not all courses are sand based, and at courses with firmer soil, I can't see the impediment from a maintainance perspective, therefore, it's one or two reasons.
Cost or Will.
I'm sure there's an incremental increase, but, I have to believe that it's not substantive, therefore, I conclude, that at many courses, it's the lack of WILL, or conversely, the desire to avoid the intended hazards.
I've also noticed that creeks/streams/ponds have been allowed to be fronted with expanded areas of "buffer" rough.
Years ago, at a club I'm very familiar with, the green committee, with which I was extremely familiar with, agreed, with the superintendent to have a buffer of no more than three (3) feet from any of the 8 streams that bisected various fairways.
Today, those buffers probably average 5 to 10 yards.
Add in all the flowers that have been planted and it's representative of the feminization of golf