I will take my cue from the aharonim who oftentimes when they wish to solve one problem, they bring in another problem and then solve both in one fell swoop:
Problem #1: Shidduch Crisis/Catastrophe/whatever you want (This post should not be taken as an indication that I agree that there actually is a problem; this is leshitaschem.)
Problem #2: High school age boys have no permissible way to channel their feelings, which can cause a problem of (to borrow a line from the gemara) ?? ???? ?????? ?????.
Solution: Every boy will get married sometime around the beginning of high school with both parties knowing that it is not intended to be their real marriage. So right off the bat problem #2 is solved. Now after high school, or when they are ready to really get married, they will get rid of their high school wives and then get married for real. But wait! The girls won’t agree to this because then they will all be gerushos. So the trick is that you give her the get and then you are mevatel it not in her presence and like magic the Rabbanan are retroactively mevatel the kiddushin and thus no one is a gerusha. (A side benefit of this is that although halachically they were never married, in actuality they did get married, thus in terms of the gemara in Sotah 2a all the real marriages will be considered second marriages thus eliminating the issue of finding your predestined match.) Now you may ask how this helps the shidduch crisis if there are still more boys than girls. The answer to that is as as DaasYochid pointed out in the other thread, that 10% of girls will be taught gemara. (Contrary to what DaasYochid said there, everyone will want to marry them.) Now these girls who learn gemara will know that Tosafos says that the trick of being mevatel the get doesn’t work if you are doing it specifically to be able to undo marriages which is sort of licentious. (Maybe one could argue that here the underlying kavana is for a mitzvah so maybe it would work, but we’ll reject that option.) Therefore these girls will refuse to get married. Which they anyway deserve as punishment for learning gemara. With 10% of the female population out of the picture, there will now be enough boys for all the remaining girls. Two problems solved so simply.