> But at that time APL was not running on any computer; and he stoutly insisted that it was unnecessary that it ever run on a computer. It was for him a notation with which he could express algorithmic concepts; and for him at that time, that seemed sufficient.

Indeed. Because both APL and Lisp began as languages for describing computational ideas, it stands to reason that they would be particularly fit relative to languages that evolved under other fitness criteria.

I was intrigued to not the opposition to APL mentioned in the article by Djikstra and others on the basis of a different mental model of computation.

Not only is that article related, it's the same article.