There aren't enough IPv4 addresses. It's not difficult arithmetic. It is possible for someone to be hoarding and someone to be wasteful and there not to be enough of something to go around. Those aren't distinct ideas only one of which can be true for a namespace.

Let's try a little thought experiment. Abe, Carol, Emma, Gerald, Isobel, Kate and Mark are at the place. Everybody is hungry. Three pizzas are delivered. Each person will be able to eat about half a pizza, or else they'll still be hungry.

Carol and Isobel announce that as Vegetarians they ought to have the two veggie pizzas. Carol eats half of hers and says she's keeping the other half "to eat later". Isobel realises her pizza has red pepper on it, she doesn't like red pepper and so she throws about half the pizza away as "contaminated". All five other people are left to share the Pepperoni pizza, they all still feel hungry after dividing it equally.

Was there hoarding? Yes Carol hoarded half a pizza. Was there waste? Yes Isobel wasted half a pizza. Was there not enough pizza? Yes, three pizzas is enough to properly feed six people and there were seven people eating even before Carol and Isobel announced they were keeping the veggie pizzas to themselves.

They already do in the form of the LIR and resource fee.