Do you agree that a bigger egg makes a bigger omelet? Well, it is the same with bulbs. The bigger the flower bulb is, the bigger the flower will be!
But the resemblance goes further than that! Like eggs, bulbs are graded by size before they are sold, with the largest ones fetching the highest price. The smallest ones, which have not yet stored enough energy to produce flowers, are sold in large amounts for low prices, often by mail-order magazines and big-box stores looking to keep costs low.
We only stock bulbs big enough to produce flowers right away in their first spring.
For more details, see this article by Bemis Farms Nursery, who also took the picture showing the dramatic difference in size between the high and low end of bulbs. (I would have taken my own picture, but our biggest bulbs won't fit in an egg carton at all!)