Dick Daley:
We had plenty of property to work with at Pacific Dunes -- probably another 100 acres of flatter stuff to the left of the fifteenth hole. We simply decided that it would be a better course at 6,700 yards with every hole on gorgeous terrain, instead of 7,000 yards with two or three holes which felt like they were "out of the dunes."
It helped that Bandon Dunes already existed and was 7,300 yards long, so that championships [if there ever are any] could be played there. For resort play, though, hardly anyone ever plays the back tees at Bandon.
As for Nebraska [or Holyoke], all the courses you're talking about are at elevations between 3,000 and 4,000 feet, so that a 7,000 yard course plays significantly shorter than 7,000 yards at sea level: in fact, it's more like 6,500 yards than like 7,000.