Is this happening to you?
You've got a Facebook group but people have been telling you that they miss your "lives" often or that they missed things and you're wondering why. Well it's because they've not been interacting.
YES, they can have notifications turned on but if they consistently ignore your posts, the algorithm, eventually thinks it's not important and will stop showing things from the group.
So do yourself and them a favor, if they've not participated in a while, drop into messenger or show up on their timeline. This will help to jolt their memory. And get them back into the habit of popping back into the group.