Its a good question
Although clearly not a chiyuv. what a zechus, Amen Yehey shemie rabba can destroy a bad gzar din, oopurtunity to say kedusha even a “simple” amen.
I understand when there are children at home, that is her primary tafkid but for the majority of her life often there is a shul close by instead of sitting around at home why not get extra easy zechusim.
It is very puzzling
Strangest of all, is when they are there. At a chausna or simcha there is often a minyan formed the women are there they can join answer amen etc , instead they hang around and shmooz yet it isnt even on the radar. I find this very strange