When you say "powerlifters", are those people who compete or just people who train? I can imagine this to make a difference.
And in any case, I wouldn't take Rippetoe as an example of good scientific programming these days. It's good for getting people into lifting, but Starting Strength has a powerlifting fetish for no good reason, and the advice to aggressively gain weight is also not appropriate for everyone (GOMAD etc.). Then recently I saw a Starting Strength video in which they claimed that the really grindy reps at the end of the set are the ones that make all the difference (for strength anyway), which as far as I'm aware is false and probably harmful, as you can do way more training volume with less risk of injury (I would expect) if you keep some reps away from failure.