Hang on, they mostly agree with each other. I've spoken to Rob Pike a few times and I never heard him call out Perlis as being wrong. On this particular point, Perlis and Pike are both extending an existing idea put forward by Fred Brooks.

Perlis is right in the way that academics so often are and Pike is right in the way that practitioners often are. They also happen to be in rough agreement on this, unsurprisingly so.

Treating either as gospel is lazy, Perlis was pushing back on dogma and Pike on theory, while legacy code makes both look cleaner on paper.

Could you be more specific?