Oh I think the replacement rate is about 1 newbie for every 12 - 15 oldsters.
Someone remarked on the aged population sitting at the Iris convention banquet, and how we have all gotten older. So many of these people got into this Iris hobby 20, 30, 40 years ago. We are not seeing that level of dedication in any other plants societies. As far as garden clubs, well, when the garden clubs continue to meet in the middle of the day at the home of a lady or two, that pretty much limits who can/will come.