It so happens that singles events, meals, or other ways of introductions (not shadchanim) might change the demographics, if boys would meet and want to date girls older than they (or their parents) would consider “on paper”. You’re right, though, that it would meet resistance, so NASI is encouraging the consideration of older girls, within the system which uses shadchanim.
Your first two ideas would have no effect, and just show lack of understanding of the underlying cause.