And the reverse biochemical process is equally misunderstood. I used to teach high school Science and everyone thought a tree's mass came from the soil.
I would more chalk this up to too little biology, too late, for people to learn well. And, frankly, it's not something everyone NEEDS to know; misunderstandings are not the end of the world.
Still, we don't normally assume that water is the primary component of "soil". The key realization is that a tree is not made of the dirt around it.