There is huge difference between multi-decade projects and "pure sci-fi" or "impossible". "Reasonable" is subjective to define, but there are many multi-decade

There is huge difference between multi-decade projects and "pure sci-fi" or "impossible". "Reasonable" is subjective to define, but there are many multi-decade projects running right now so I don't think of multi-decade projects as unreasonable. Things like sending man to the Moon or building Space Station would have been deemed "pure sci-fi" with the approach of the parent commenter.