A not-so-young lady once told me in a milonga how puzzled she was, when looking at all these cute chicks getting all the dances they wanted, while she, as a more qualified dancer, should have got, at least, the same amount of invitations. She told this as a way to suggest that maybe I should invite her. We danced a while (well, ok, we went on the floor, I made my clumsy steps, and she nicely ignored the basics I was leading to replace them by the
beautiful sequences she knew. Afterwards I had another chat (When you're a beginner you don't venture that often on the dance floor, so you have time for socializing) with the local instructor, and I drove the discussion on this subject, asking him why leaders seemed to prefer attractive beginners to skilled, yet elder, ladies.
"Old doesn't mean good", he replied, adding that in most places of the world (except Buenos-Aires), tango's popularity was a somehow recent phenomenon. So while sixty-year old portenas have about 45 years of tango (and he would beg for a dance with them), the one lady with whom I chatted in this one milonga had been dancing for "only" five or six years, taking few classes and learning mainly in situ
. On the opposite,
he had noticed that damzels of the younger generation had a real will to learn properly, to learn to follow, to wait, to make themselves light in the leader's arms. I objected that this was maybe an instrutor's point of view, that the way this lady danced seemed beautiful to me, and that a five-year experience was already quite much. "As opposed yo your own experience, sure it is much, but the truth is I don't like to dance with her, as she breaks my back with her weight, and reacts late to what I lead, unless I use some strength, which I don't want to as I am not getting any younger myself."
So here is the rhetorical answer: leaders prefer to invite younger women because they dance better. As simple as that.