JP - you may very well be correct that Gilmour was speaking figuratively, and your other comments are also on the money IMO.
My point, maybe poorly made, is that unfortunately, there are lots of guitarists / people who are so desperately seeking magic bullets and simple answers that they take what other people say very literally, and this is how myths develop or morph into perceived "fact" that are passed and perpetuated endlessly. Not to resurrect my least favorite topic here, but tonewood is the perfect example. There is no "tone" in wood. It does, to a certain degree, influence tone. Similarly, there is no "tone" in one's fingers, there is no "memory" in one's fingers, there is no "speed" in one's fingers, but how you use your fingers affects these things. Taking a commonly made statement like "tone is all in your fingers" leads to a literal translation and conclusion that my poor tone is because I have deficient fingers, which is total hogwash.
Your point about relaxing is a big one I think. As one approaches that fast lick, it's very natural to tense up in anticipation, and even pick harder in an attempt to blow through it. I know, I have done it countless times. But that is exactly the wrong thing to do. Relax and pick more lightly, and chances are you get through it much more successfully. That takes significant discipline when first learning something. After the sequence is firmly implanted in the brain, it becomes easier to do because the brain becomes more efficient at multi-tasking those specific actions. It would be a fascinating field of study I think. The pursuit of speed may not be totally without merit, as it is quite possible that improving speed capability, most likely improves one's slower playing proficiency also.
Tom