I gotta new angle for ya...I don't believe they are looking for a mature daddy figure. Or gold digging in general. I think they are less intimidated by the older males. We older guys are laid back, more apt for conversation, and I think the young girls misread that as older guys not being as sexually agressive.
I mean watch some young guys out in a public environment (bars, parties, whatever) they are being aggressive, extroverted, doing the ole dominant Alpha male thing. Some inexperienced girl might read that 2 ways...1. Dumbasses or 2. out to score big, score now, and move on.
Reminds me of the old farmers joke about the old bull and the young bull sitting on a hill top...
Young bulls sees all the cows grazing below and says " Hey lets run down there and mount up a cow"
The old bull says "nah, lets walk down quietly and mount them all!"