I don't know why it's so rare, but I do know that women who are paying attention appreciate it.
I first got introduced to the idea by an aunt who carried a 12 handicap well into her 60s. I mention a course we should play, and she'd ask, "How long is it from the forward tees?"
Anything over 5,000 and she wasn't interested.
Now,my wife and I are approaching 60, and it's the first thing I look at. She's still plenty long enough to play at 5300, but 4,800 is WAY more fun.
I have lost a lot of distance in the last couple of years, and I am learning to appreciate courses that are in the 5,900 to 6,200 range. If the course is fast enough, I can handle 6,600, but that's rare in the U.S.
What's amusing is when an older course adds new forward tees, the ladies usually refuse to play them. My mother has played at Mesa CC for years and that happened there. Their argument was that it would hurt them in interclub matches, because their handicaps would go down.
Ken