NASA stands for National Aeronautics and Space Administration. It was formed from a pre-existing agency, the National Advisory Committee for Aeronautics (NACA), that did amazing work advancing the field, and that work never stopped within NASA.
Also, to be clear: between Milner's two (fantastic) projects, he has committed $200 M, to be spent over roughly a decade. NASA's budget is about $19,000 M annually. For fast, efficient progress we need both—large amounts of government resources as well as private-sector funding of ideas that NASA and NSF are overlooking or not prioritizing for whatever reason.
So do I understand correctly that you're saying that NASA should keep running indefinitely because they're spending $19B/pa? Isn't the logic here reversed?
No. Your claim was that the government should let Milner et al. "take the front of the stage." Their work is fantastic, but it is focused on some narrow but important topics. There is a vast amount of other progress continually being made by NASA. For a healthy ecosystem, we need both sorts of actors (along with others) building on each other's efforts.
The job of the DOD is to run the military. The job of the EPA is to protect the environment. What is the job of NASA? I'm arguing that there is no such thing, and the $19B could be better spent on other uses (perhaps even by the NSF).
(That's actually the original 1958 version. It's been amended occasionally since, but that will give you the gist.)
There are specific things I would alter about NASA's current course (including killing two projects worth a total of about $3 B per year) and I would amend the National Aeronautics and Space Act to alter its long-term trajectory regarding human activity in space, but much of NASA's job has been clear for decades.
Also, to be clear: between Milner's two (fantastic) projects, he has committed $200 M, to be spent over roughly a decade. NASA's budget is about $19,000 M annually. For fast, efficient progress we need both—large amounts of government resources as well as private-sector funding of ideas that NASA and NSF are overlooking or not prioritizing for whatever reason.