AAQ: Do we have examples of Klal Isroel using polygamy as an emergency solution? Or at least, at the times before R Gershom increasing polygamy from a rare occurrence to a frequent practice?
No one suggested making polygamy a “frequent practice”. Even permitting it on an infrequent basis, as needed only with rabbinical approval, can alleviate the disparity in numbers. If even a small percentage of husbands took a second wife, that should correct the current imbalance to a great degree.