Again, I'm playing devils advocate here to highly a cynical take. This isn't my position.
The crab that waved the others down doesn’t benefit more than any other crab, it’s just a mutually beneficial redistribution of shells
You're assuming a perfect distribution of resources equal to the needs of all, but studies show it doesn't always work out that way and there's a hierarchy and a struggle for the prime resources in the hermit crab society.
"In the field, we also occasionally observed 2 or 3 tug-of-war queues radiating out from a single vacant shell, with the largest crabs in each queue struggling to gain controlof the vacant shell. Such tug-of-wars between multiple queues appeared to inhibit vacancy chains as in some cases this situation lasted up to 4h without any crabs moving into the vacant shell. These findings indicate that the formation of hermit crab queues and other linear dominance hierarchies involves more complex social interactions than previously thought(Chaseetal.2002)."
source: Social context of shell acquisition in Coenobita clypeatus hermit crabs.PDF
Once again, I don't have a horse in this race, I'm just participating in the discussion, not advocating policy or reflecting my views on our human society.