Even in normal times , new empty brass vs generic loaded ammo has slim difference in price .
There are niches for new brass : Particularly high quality benchrest quality brass , handloading for rare or wildcat calibers , etc . But for common mainstream calibers , with mainstream expectations , indeed it's more cost effect to buy reasonably priced loaded ammo , and turn it into once fired brass yourself .
With .223/ 5.56 , the demand for loaded ammo is still high enough , that mfgs put the priority on using the available cases for loaded ammo .