_Everything_ is evolutionary, if you think hard enough. But I think you're discounting the step between "reusable rocket research by NASA in the 70s" and actually building a production system.
"SpaceX's research is almost entirely funded by government sources"
I don't believe this is true. Do you have sources for this claim? The USG has purchased services from SpaceX, the income from which SpaceX has then used to develop reusability. But that's not the same thing as "the USG funding SpaceX's reusability development." In fact, the government missions initially specifically disallowed using reused boosters or Dragons.
"SpaceX's research is almost entirely funded by government sources"
I don't believe this is true. Do you have sources for this claim? The USG has purchased services from SpaceX, the income from which SpaceX has then used to develop reusability. But that's not the same thing as "the USG funding SpaceX's reusability development." In fact, the government missions initially specifically disallowed using reused boosters or Dragons.