No amount of letters and community initiatives are going to persuade a 19yo girl whose peers are getting married to risk her entire life and wait on the sidelines. What's more likely to happen is the Rabbonim telling her to be chilled and wait are going to make her more picky and less willing to compromise, increasing her odds of staying single until she has to compromise much more.
More chinuch towards compromise, tolerance, and individual responsibility would go a long way towards solving the crisis. A big part of it is singles who are too judgmental to date each other, and then it's the girls who are complaining while the guys aren't as bothered, like chazal taught יותר ממה שהאיש רוצה לישא האשה רוצה להינשא. Too much girls school emphasis is on being critical and not following the heart, when oftentimes it's the opposite that would be more helpful.