[gwc]

If you actually read the paper, I think you will find that the authors do not, in fact, make the proposal that you are assuming.

"Should the organization hire (i) the person with the highest score, (ii) 20 people with the next 20 highest scores, or (iii) 20 people randomly selected from the applicant pool? ... In this paper, we provide conditions under which iii is better than ii."

Further, the paper is not purely theoretical, as you suppose: they then go on to provide such conditions and describe the 'computational experiment' using AI agents that they used to explore and verify their hypothesis - keeping in mind that fundamentally, their hypothesis is simply that there exists conditions under which functional diversity trumps maximized individual ability.

It's worth noting that they make a key distinction between functional diversity and identity diversity. While they do correlate the two in their abstract - with sources - their conclusion does not speak to the latter at all, instead focusing on the former and "diversity in perspective and heuristic space".

You may certainly disagree with their conclusions, but it is unfair to construct their argument as a straw man consisting solely of theoretical ideas and stupid assumptions.