TMac,
As always, you make some keen observations and raise interesting points. We've had some discussion previously on the use of heavy equipment in course construction through the first quarter of the 20th century. While some machines were used during this time, it is my understanding that they were extremely primitive, difficult to operate, costly and more useful for very large scale projects. I do not have much interest in equipment (construction, golf, or otherwise), so I am willing to concede your superior knowledge in this area.
In reading much of the same books you have on golf architecture, I got the general impression that course construction back then was pretty much a labor-intensive, back-breaking process. I learned through my own conversations with two engineering professors at OSU who worked on a WPA crew to build the courses there that much of the work was done by hand. They remembered hauling-off clay material from the lake by wheel barrow and building the greens. Perhaps their recollections were fuzzy, but they seemed very credible to me.
In any event, courses during this period were routinely built for under $100,000, including the land, and money was definitely an issue at most places. I would not consider Macdonald and Thompson to be "Minimalists" in any definition of the word. Both had access to considerable money and built to a more manufactured standard.
This past June, I had the opportunity to observe some construction on the Red Raider course at Texas Tech. I watched one of Doak's and Urbina's expert shapers create the last bunker on the course with a piece of equipment that, under the operator's control, was like a surgical instrument. The agility of this machine and the way the shaper handled it was just short of amazing. The "old guys" couldn't even dream of this capability. I also observed several huge earth movers and assorted other pieces performing like a symphony orchestra. The volume and detail of the earth work was unreal.
As noted earlier, there was some movement of earth at that time, but much of it was in the areas of the greens and the tees. I do believe strongly that "Golden Age" architecture, as good as it is in the top tier, could have been better on a wider, more consistent basis. Specific and general examples: CPC #18; several of the par 4s at PB; the ridges or humps in fairways which make for blind tee shots; highly elevated, built-up grees with relatively flat surrounds (e.g. Naval Academy course); extremely compact, dangerous routings.
On balance, I think that equipment and money have been a blessing to modern architects. Despite much stronger environmental constraints and higher land prices in metropolitan areas, some very good courses are being built that would not have been attempted during the earlier time. It is very likely that new construction technology has resulted in numerous excesses, but for most competent, artistically oriented golf architects, this must be a very exciting time to be working (notwithstanding the current shape of the golf economy).