Charles Darwin, almost a century and a half ago, did understand. His book, “Earthworms”, published in 1881, was the result of years of study into these seemingly insignificant creatures. In his manuscript he noted “It may be doubted whether there are as many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.”
If one digs into leaf mold, or into really good soil, tiny white filaments resembling spider webs can be seen spreading through the soil or leaves. This is mycorrhiza. Though deceptively small, a teaspoon of good soil can have eight or nine feet of the tiny strings.