SpaceX almost went out of business on a few occasions, had tons of funding, wrote off many rockets in the process and eventually, after 12 years had a commercial product.
No one has said what Hill wants to do is impossible. His timelimes are impractical, his funding is limited and DARPA/NASA won't be bailing him out if it doesn't go to plan.
There is no pixie dust that will just make the challenges disappear, but I continue to wish him well, it would be marvellous to have fewer of those Robbie Helicrapters creating noise pollution and see something much prettier in the skies.
I just don't see it happening anytime soon.