I feel that one should take caution not to make such assumptions as the resulting logic ends up extending to “natties should only do fullbody programs because splits only work for assisted lifters or the genetically elite” and “every bodybuilder other than the ones whose training methods Rippetoe and I agree with is doing it wrong”. Also, other than Serge, we are only looking at a brief snapshot of their training, which may not be the same throughout the year, and the accuracy of what they are actually doing during the workout, e.g. the weight used with every set when pyramiding up to a top set, is limited to the accuracy of the person reporting it.
Regarding Serge’s “pump training”, IMO it is either something he came up with as a novel and interesting training style while selling whatever services he was offering, or it’s something that he may have been doing at a later stage of his career. I personally do a different variation of “pump training” when maintaining while giving my joints a break from heavier weights.