This makes me reflect about the dynamic nature of truly wild streams... rivers in Puget Sound never needed that kind of human intervention because nature blows out root snags with regularity.
Even when really bad log jams occur, they are not cleared by the hand of man. First of all, there are so many rivers out there that even people with driftboats just go elsewhere. Second of all, these create interesting pools. Brian and I found willing takers on the Elwha one fall evening. I hooked and lost a solid ten pound chromer and Brain rose two to a waking fly - all along a submerged tree laying along the far bank by the apple orchard hole.
That is not to say that erosion and thus washouts do not occur more now than in biblical times, I am sure they do. I am just realizing that anglers out in the PNW do not intervene in felled trees and log jams in rivers for whatever reason, the most of which I believe is availability of alternatives.