That's an authority argument, even if in this case a strong one. What you seem to be overlooking is, that merely from this one quote, we cannot conclude, whethe

That's an authority argument, even if in this case a strong one. What you seem to be overlooking is, that merely from this one quote, we cannot conclude, whether that is really all of methodology that went into building the Voyager 1 and 2. So while it is a witty quote, it doesn't actually tell us much, without additional statement, that we don't need to look any further for other methods that were applied.