My point stands as well:
"If, in these conditions, humans can't build a rotating habitat, then I'm sorry to say we'll never expand into space: we just don't have the brain power - by a significant margin."
We built hugely expensive and not very safe ships that could at most get people to the moon.
We never solved the problem of spaceflight - not even close.
As for your comparison between centrifugal gravity and spaceships:
Centrifugal force creating gravity is a non-problem, not building spaceships.
Ah! So building spaceships is a problem, but building spaceships to do things they've never done before is a non-problem. Got it!
Again with moving the goalposts:
Centrifugal force creating gravity is the same as building spaceships for you? Really?
Nope, I never said that. All I said, in the post that kicked off this sidebar, was that doing that on a practical spacecraft is not a "non-problem", as you'd called it.
Not all problems are equally problematic, obviously.
But in practical spaceflight, when mass is a premium, nothing is trivial. When mass is a premium, everything's a problem.