Why is the biological method of insect suppression more progressive than the chemical one?

The biological way to control insects is that their natural enemies or parasites are brought to fields or other places that suffer from pests. They kill insects naturally. Also, after a while, insects leave that area on their own and will not lay offspring there because of the large number of enemies. The chemical method is effective, but only for a while, as the pests can adapt to the poison and multiply. Therefore, it is necessary to treat the fields with chemicals several times per season.