Without a solution to a new problem post-gimmel tamuz you are writing off thousands to lives of shnorring and relying on their spouse's meager teaching salaries.
This merge is a bit of a stretch for this topic, but I think that it's within the theme. Might split it off again onto it's own topic.
I believe that a solution is currently in the process of a metamorphosis.
The plan is to adjust and create shifts in state-wide vs. city-wide vs. niche Shlichus.
It's acceptable to work a half day and do "outreach" a half day or any proportion/combination of learning,
adult education, youth groups, Friendship Circle, etc... Therefore, it's now helpful for Mesivtas to teach these skills to enhance their future Shlichus: graphic design, movie editing, music, etc..
Amazingly, there have been bochurim who have scored in the 99 percentile in standardized testing
of math, science, during high school -- even with their limited Mesivta learning (you were one of them?)
It is possible to do -- the biggest challenge that I see is not the academic abilities as much as the abilities to focus, respect, see positive perspectives, and to LIVE life daily with a good sense and balance of self-confidence, Midos,
along with having a sense of bitul, appropriate behavior that would make the Rebbe proud -- not just in davening and academia, but also integrity, love for a fellow, mankind, etc..