This is by no means an all-or-nothing selection (as the impression is sometimes given). Rather, the alleles are retained.
The Venus flytrap, like all carnivorous plants, had no use for its insect-trapping function unless it also had an insect-digesting function. And vice versa.
A biologist in our network worked as a postdoctoral researcher at Harvard. He recounted how about a quarter of the postdocs he encountered were at least sympathetic to design arguments.
A dependency graph is not any old ad hoc hypothesis. It was posited because it is something that we observe in software engineering.