The pairing up of Chassidim to livish was mentioned; it won’t work in large numbers because of the cultural differences.
I disagree. First of all, it already has been happening in large numbers since (at least) the end of the Second World War — with both groups now living in the same areas in large numbers. No, perhaps not a Satmar Chosid with a Ner Yisroel family girl. But there are many Chasidim and Litvish that are not far apart hashkaficly as it is. We can and should encourage more of it. Especially considering it helps both age gap issues — the Chasidim with the excess boys hand-in-hand with the Litvish with the excess girls. Plus, it can work immediately. Including the current crop of older 30 and 35 and 40 and older year olds, that the close in age work by NASI doesn’t really address — as well as the younger generations. This point is not intended to detract from any of the other solutions.