Mike, I've struggled with this over the yrs. I could machine rake 30 bunkers in about 2 hrs. And another couple hrs to hand rake the edges. So, figure 4 hrs/30 or 60 in a day. Now if there are no sand bunkers, that same area still needs to be mowed but only at 1/3 the frequency (and no hand work). Plus most sand bunkers need to be edged a couple times a season. If the sand bunkers have elevated faces, rain can cause sluffings - more hand work.
Bottom line, sand bunkers are more expensive to maintain than grass. However, the incremental amount depends on the size and efficiency of the crew. The big bugaboo is HAND WORK. No one wans to do it when they can just be sitting on a mower all day. But then I see guys married to weed-wackers all day long because someone planted Bluegrass around the trees. Go figure. It all boils down to priorities.
Personally, while I think, given the right site, one could do a good bunkerless course, I think the general public would look at it as if something were missing.
GoogleEarth where the old bunkers were The oneson the west holes wereput in by my father when he raised those holes out of the floodplain. The little pot on the 17th on the east is all that is left from a ribbon, shelf bunker that I put 3/4 the way around the pond I dug for irrigation water. BCG did pay for the improvements, but you can see they have already taken some out. Why, because it affected THEIR bottom line.
I wouldn't be surprised if you see something like this in Modesto.