The government doesn’t buy ammo from Wally world.
They get it via contracts with manufacturers.
It takes time to write proposals, find potential suppliers, evaluate them, then award the contract.
Bureaucracy moves s l o o o w l y.
Why would anyone want to buy “made in China” ammo. If their quality control is like some of the other products we have heard about in recent years, I sure would not want to bet my life and safety on it.
The ammo shortage is too broad for a government buy up. At least that’s how it appears.