There is a thread over on cointalk related to Instagram and many members are active participants on the coin community on it. Majority are the younger generations. It's very possible, whoever wrote that article, never bothered to check social media like IG, facebook groups and or even reddit. It was just a broad generalization that no younger person is into any outside activity but playing mobile games or making stupid dances on tiktok.
I read several numismatic magazines, especially the "Numismatist" and there's been several articles written by females alone, couple in their early 20s. Some may not collect, but they work in the auction houses dealing with coins themselves too.
It's a shame to see this organization go, but don't discount the fact that women may be smaller in numbers or not at all. Being that many of these hobbies are male dominate, maybe they like to keep a low profile so they don't catch the wrath of men who think they are superior or have sexual jokes made at their expense. I see and hear about it pretty often.