Reducing disparity within a company is surely achievable and almost inevitable.
I don’t personally believe it’s desirable in endeavors where value contributions can be heavily unevenly distributed, because it likely leads to the company being unable to employ the very top value contributors as another company can [and likely will choose to] pay them more, which is consistent with the main claims in the article.
In California for example, the equal pay act requires 'equal pay for employees who perform “substantially similar work,” when viewed as a composite of skill, effort, and responsibility.'
https://www.dir.ca.gov/dlse/California_Equal_Pay_Act.htm
Someone who contributes more inherently must have greater skills and/or put in greater effort, and likely greater responsibility, given they are accomplishing more tasks.
You can pay differently based on a seniority system, a merit system, a system that measures earnings by quantity or quality of production, or another bonafide factor such as education, training or experience.
Here's a copy of that law, it's pretty short.
https://leginfo.legislature.ca.gov/faces/codes_displaySectio....
No place is (yet) mandating perfect sameness of the latter and I don’t expect that to be policy in my lifetime or while we have the concept of money as a society.
Because directly stating "the authors of this paper misunderstood the purpose of pay transparency: it doesn't matter what the average pay becomes, as the goal was to reduce pay disparity" is a more forceful statement that makes more assumptions and simply isn't as friendly as asking it in the form of a question (which might be taken as a socratic dialog, but that also feels more friendly to me than a lecture).
When you make statements about what you want, that's good for discourse.