I suspect that these members already have a summer course somewhere else. If you are a local member, you are at ACC or some other club in the area.
I remember, decades back, hearing that members of ANGC don't actually play ANGC all that often. Play it too much and you might receive an invitation to discuss your prolific play. Being a member of ANGC is not about the golf.
ANGC has a course for the distance-challenged members. It's the short course. Also, I suspect that the older members don't really care what score they are shooting, nor which bets they are winning. From the membership perspective, the second course would be odd, considering the infrastructure they've put in place.
So ... the only reason for a second course would be to enhance what is already in place, for the female amateurs and professionals. I'm certain that ANGC would like to host all three rounds of the ANWA at the club, but understands that the course would get three times the tournament play it currently does, a week before the big event.
If ANGC builds a second course, I believe it would serve to host the ANWA and someday, the big event for the women. I don't believe that the Dinah Shore is cemented as a major for the LPGA, so if ANGC came out with a proposal to host an event in May, it would be received quite well by the LPGA and LET. There are three events in May of this year: San Francisco, New Jersey, and Las Vegas. That leaves an available week, and why not celebrate the first major of the year in May at ANGC, then the PGA in June, then the US Open in July, the Open in August, and the Evian in September? Quite the five-month run.
Edit 1: Angela Moser gets at least co-design role;
Edit 2: Course #2 allows the women to write their own story, so that they are not forever compared to what men have done in the "other" tournament.