So, this is what your 2000m² would look like if they were to represent the global situation. More than half of the field would be cultivated for just four crops: wheat, corn, rice and soybeans. Other cereals, tubers and oil crops would also be dominated by very few types and varieties of plants.
Of course, the smaller gardens are full of hundreds of varieties, but the area they cover is only a small fraction of all arable land. With the exception of rice, the larger part of vast monocultures is dedicated to non-food uses, such as animal feed or fuel.