Ian,
30+ years ago, I noticed the intevening "buffer of rough" becoming more prevalent with bunkers and water hazards.
I believe that it's introduction had nothing to do with maintenance and everything to do with the rise of that ugly demon, "fairness"
I watched green committees expand from a few interested members to 10+ % of the membership.
I observed members lobbying for their self interests, take hold.
Rarely did green committee members view the game, golf course and maintenance in any light than their own perceived needs.
Hence, I use the term "safety net", because that's what I observed.
On two holes in particular, one with a creek fronting the green, and on another with the creek bisecting the DZ, member after member claimed that the hazards weren't fair, that they hit great shots only to end up being penalized by the creek.
What they really meant was that they chose the wrong club, struck it exceptionally well, and ended up being penalized for a well struck shot. They hadn't a clue that their poor choice of clubs was really the culprit.
I saw buffers of rough introduced, and then expanded from three feet to ten yards.
With the bunkers, the buffers of rough often extended one to two or more yards from the bunker.
Again, the complaint was that a well struck shot shouldn't end up in a bunker.
They completely ignored or were ignorant to the fact that they hit the wrong club and/or in the wrong direction.
Those crutches/aids, which golfers want, to avoid the consequences of poor judgement and/or poor execution should be removed.
And, I've begun noticing this trend and applaud it.
As to cost, should the game, the architecture, the field of play be perverted in the name of cost and fairness, or do you seek a form of purity in the architectural features, one where the features shouldn't be diminished because a golfer fails to think and/or execute ?