Mike,
Yes, I should have included you.
I don't see "commercialism" as an influence at Private clubs, but I'm open to hearing that premise.
I wonder if the trend away from non-returning nines had to do with the expanding popularity of golf and the "beginner", those that didn't want to experience the rigors of 18 holes, because they felt their games weren't up to it ?
Even today, many clubs have formalized " 9 holer" groups.
Donald Ross wrote the the ideal routing would be two returning loops, yet, Pinehurst # 2 doesn't come anywhere close to returning. But, I don't believe that # 2 was ever intended to be a private course.
Does siting the clubhouse predetermine or limit the routing ?