I love articles that argue convincingly for a new paradigm. There is likely much more to gene expression than is visible to the Mendelian eye.
But the new gene didn’t create the new trait. It just made it easier to keep a trait that a change in the environment made valuable. The gene didn’t drive the train; it merely hopped aboard. Had the gene showed up earlier (either through mutation or mating with an outsider), back when you lived in the forest and speed didn’t mean anything, it would have given no advantage. Instead of being selected for and spreading, the gene would have disappeared or remained in just a few animals. But because the gene was now of value, the population took it in, accommodated it, and spread it wide. In other words, a mutation might occur after an organism has accommodated an environmental change. The mutation sticks because it is relevant.
This makes a lot of sense. Most appealing about this article is the author's implication that there are many things we don't yet understand, rather than the one-theory-fits-all assumptions about genetics.
btw, while reading the story of the grasshopper/locust gene expression, I couldn't help thinking about the violin/fiddle.