Of course that's entirely his supposition based on nothing more profound than his intuition.
As we've all noticed before, people speculating outside their fields of expertise tend to surmise that problems are more difficult to solve than they really are, and that solutions to them must fall into certain intuitive, brute-force categories rather than capitalizing on innovation and simplicity.
Jay, I have seen this before (I can't remember exactly where) in trying to understand the power of lift.
Consider a fully fuelled and laden Boeing 747-400. Depending on the model, its all-up weight is around 900,000 lbs (around 400 tons)
On the face of it, if you know nothing about lift, and going purely on intuition, it just cannot fly. Even if you had lift explained to you, it seems totally counter-intuitive, that the fact that the only reason this behemoth can get in the air and stay there is because the airflow around the wings can create near a million pounds of upwards force. It just doesn't seem possible, yet, it is.
Yet, people don't say that lift is a hoax, or that flight doesn't really happen, even if they don't understand it. They are prepared to get on board passenger aircraft in their millions every year without having the foggiest understanding of exactly how this 400 ton monster flies. They take it on faith, and on observational experience that it works.
Spaceflight, and flight to the Moon however, don't seem to get the same trust.