“The letter” that keeps getting mentioned has signatures of R”Y who encourage closer in age shidduchim, nothing more, nothing less. My R” Y is signed onto that letter. It is all he signed on to. anything else espoused by Nasi and claims to be endorsed by the signers of the letter is not endorsed by my R”Y and in fact, each signatory to the letter would have to be asked if they agree. Be that as it may, I am aware of NO R’Y who has advocated bachurim en masse getting married earlier as a solution to anything. Bachurim, hopefully start to date when they are mature enough to handle the process, not sooner, no matter what their age or how many available bachurim are needed to match up with available girls.
Over shabbos, I overheard this very conversation between several married women (my wife among them) and an older single girl (35+). Someone made the comment that there are more girls than boys, this single quickly corrected that statement to, there are many more “good girls” than there are “good boys”. I didnt catch the specifics of this distinction, but the way my wife understood it is that this girl is not lacking for dates (nor was she), even at the age of 35. The girls feel that there are so many more “good girls” than available “good boys” (however they define the term).