Yeah, my parents were both hoarders; my mother was worse than my father. And like your grandmother and mother, I think it was mostly because they were poor growing up. But they did love to tell me stories about how clean everything was back in their day; how you could just stop by a stream and take a drink or pick berries and eat them without washing them, etc.
Ah yes, the containers that'll come in handy someday! I know them well. I've done it. I used to save jars, because I'd need them for the pcikles I was going to make. I haven't made pickles in about 20 years.