> it’s why the suburban ground in California looks — and acts — like concrete.

Look, I am as fanatical about soil biome issues as anyone that you are going to find, but your assertion is overly simplistic. If you look at a soil type map for large parts of Sili Valley, you will see big chunks labeled "Adobe". As in clay. As in it doesn't percolate. As in naturally sparse in organic matter. As in gardening contractors in Milpitas own not rent jackhammers, and it has nothing to do with the long term effects of leaf blowers.