Sooner or later, it all comes down to money.
We know it happened in the depression. We know it happened a lot in the 70's recession. And I have gotten two calls this week on my designs to come consult on removing unnecessary bunkers that they feel are raising their costs. (This in addition to three more courses who are doing it without my help since 2001)
If it isn't money, its speed of play, which translates to money for the Owner, at least in his mind.
I got to thinking about the bunker eliminations I have been involved in. Usually the powers that be have gotten rid of the bunkers that they feel see too much play or not enough. Exactly how they determine that, I am not sure, but like porn, I guess they know it when they see it.
If it is design, perhaps its the original minimalism, no? If Augusta can be great with 30 or so bunkers, why have more? I think that had a big influence on early bunker reductions.