I disagree respectfully, Joe. You have used the biology simile so lets stay with that. Our bodies and those bodily functions you mention are not merely chemical-hormone-regulated but biological communities, or biomes, of microbial life. Most of our interior DNA is not ours, but I could not write this or remain breathing without that part.
Hoarding appears to be antithetical to community behavior but it is a natural function. Some of those microbial members of my community hoard oxygen to help me maintain the life of my cells. So too, humans hoard, saving for lean times by harvesting excess in good times.
Because this is a natural instinct for us, imposing external rules meets with natural resistance. The cultural aikido move is to channel those instincts into good hoarding, or hoarding as a group and for the group. You can see this in the typical philanthropic patterns of high-net-worth individuals: local symphony orchestras; college endowments; donations to child welfare causes; and so forth. They are donating to strengthen a community. Their community.
Perhaps what is needed is a shift from lambasting hoarders to praising their instincts to secure their tribe and gradually widening the perspective of what we mean by their tribe, and what it really needs right now.