I think you misread the GP. These "mid and senior devs" are writing documents not documentation. They're not writing comments or wiki pages, they're writing designs docs for new systems, proposals for cross-cutting initiatives, etc. They're taking their knowledge of the domain, its issues, and general wisdom and applying it at a scale larger than a single developer's output.
In theory, this makes perfect sense and is a great way to amplify a more senior developer's impact compared to just coding "the hard stuff." In practice, unfortunately, this leads to a "doc culture" where there's often too much focus on the writing & documents and not enough on the coding & getting shit done.
For example, look at Amazon. Writing is considered a core SDE skill, yet atrocious code (especially from more senior "lifers") and shitty half-solutions are seemingly desirable. Promotion at Amazon is about telling a story of your impact in your promo doc, not about explaining to the powers that be that you're a kick-ass engineer who needs harder problems.
In theory, this makes perfect sense and is a great way to amplify a more senior developer's impact compared to just coding "the hard stuff." In practice, unfortunately, this leads to a "doc culture" where there's often too much focus on the writing & documents and not enough on the coding & getting shit done.
For example, look at Amazon. Writing is considered a core SDE skill, yet atrocious code (especially from more senior "lifers") and shitty half-solutions are seemingly desirable. Promotion at Amazon is about telling a story of your impact in your promo doc, not about explaining to the powers that be that you're a kick-ass engineer who needs harder problems.