Now Brian, what would Prof Dawkins say to you if you referred to something as interfering with "normal process of ... evolution"? I'm sure he'd point out that that's a progressivist viewpoint, and assumes that there is some goal towards which evolution (musical or otherwise) is directed.

That it has changed by exposure to "source" recordings is undoubted; but just listening to early revivalist recordings, or looking at the often sanitised published arrangements suggests that the access to the recordings has allowed later revivalists to remove a layer of interpretation that (to my taste) we are better off without.