You're right! An editor probably reads more than all their authors combined, and provides feedback on what isn't up to standard. My engineering managers were expected to do the same. An engineering manager who does not read all the code and PRs is as helpless as an editor who cannot read. They cannot know who is performing well, who needs coaching, who is all talk but makes a mess, etc. The idea that engineering managers can be excellent but code illiterate keeps showing up, but makes no sense at all.
The sentiment I've seen is that a great people manager who trusts their engineers despite not knowing much about software can still be an above average manager.
Given that the median manager seems to be throughly mediocre, an above average manager even if they can't code or read code seems desirable.
I remember reading about an actual observational study on this -- I think on HBR -- and the conclusion was basically that managers that are technically skilled have much happier employees on average.
Another finding from the same study was that the statements "I feel like my manager can do my job" and "I am not looking for new work" were strongly correlated. (This sounds like the same thing but isn't.)
In other words, you have to be one he'll of a people person to make up for cards stacked against you.
I think either end of the spectrum is fine: highly skilled / can do your job if needed, or not technically skilled at all / honest about it / tracks schedule / delegates all technical authority. The messy middle is where the problems happen.
You can't be a coach and a player. It doesn't work. Having technical skills and being able to make or weigh in on big picture decisions is great. But you have to trust your team to do their job, even if it isn't exactly how you would do it. Does it meet the business need? Does it make sense strategically. Is your team staying unblocked? Are you being reactive or proactive? Are your team members growing and improving?
I must live in a alternate universe. At a previous company, the last two "engineering managers" I've worked with definitely could NOT read code. They did not read PRs, other than perhaps the title and Jira it linked to. Any technical management, including PR and design review, was delegated to the staff or principal engineer(s) on the team.
Maybe we do. Wouldn't a better analogy be professional writers moving toward an editor/director role?