The Rabbonim can be Mattir the Cherem Derabbenu Gershom. Some wealthy men can afford several wives. Many singles have money of their own. Sometimes where a woman has fertility issues, having several wives should be welcome by all.
Especially in the US and Israel. The Cherem wasn’t meant for those places. America wasn’t even discovered in his time.
True, if the Chilonim are deriding us for our busses they will have a field day with this Hetter – but who cares what they say. We have a problem and we must find creative out-of-the-box solutions.