Each of these ten is a highest-end private, or a highest-end public. All can afford to do what they damned well please. I would suspect that the courses and clubs that don't Daddy Warbucks among their membership/guest rolls, benefit from bringing the 9th back to the clubhouse. A question of art versus economics.
My point was precisely that these courses did what they pleased, instead of following a stupid formula, and that CAUSED them to be the highest-end private, or highest-end public courses. [Of course, the stupid formula had not been agreed as necessary when most of them were built.]
Not returning to the clubhouse at the 9th certainly results in SOME economic loss, though it would vary from place to place. One of my clients who insisted on returning nines [and almost hired someone else because I hadn't done it at first] was Julian Robertson at Cape Kidnappers -- he said if Shinnecock Hills had it, we should, too. So, I changed the routing to fall in line, although I really doubt that many people go to Cape Kidnappers and only play nine holes -- and the staff there would happily go out and pick you up from anywhere on the course, anyway.
The important thing about these two rules is that they limit the number of options you have for routing a golf course, much more than most of you understand [and more than Jeff Brauer will admit to himself]. If you can't use that canyon for another beautiful par-3, because you've already got four, your course suffers. If you've got to get back at the ninth hole, you can't use the cool property that's more than a mile from the clubhouse, because you can't get out to it and back again. [Or, you have to move the clubhouse location to someplace less ideal . . . Barnbougle Dunes had to have a long narrow east-west routing, and for returning nines we had to put the clubhouse in the middle . . . which meant that either #1 or #18 was going to play into the sun.]
I have tried to maintain an open mind about par, so as not to limit my options. I don't have anything AGAINST par-72, I just don't have anything FOR it, either. I am happy if par for each nine comes out to 35, 36, or 37 [and occasionally 34]. But if you just let those results fall at random, the odds that you're going to get a course that's par 72 are three out of nine: 35+37, 36+36, 37+35.