tl;dr:"Many leaders mould the organization in their image or the image of the past workplace. Engineering leaders brought into embattled organizations tasked with stabilizing the chaos are often heavily incentivized to do this. Many a time these folks, in my experience, tend to fail harder and more often than those who try to learn the organizational ropes and tailor their leadership style to fit the organizational culture."
tl;dr:Knowing how your org works can be: (1) Knowing what technical skill you need to invest effort into that will actually be rewarded. (2) How to build lasting relationships with other people on your team or organization that will ultimately dictate the success of a project. (3) How to effectively pitch projects or improvements and see these through to completion. (4) How to navigate ambiguity, and more.
tl;dr:The costs incurred of hiring a junior engineer isn't always realized. "If a team isn’t willing to invest at least 1–2 years, they shouldn’t be hiring junior engineers." Investment comes in mentorship, manager's loss of productivity, and other ways outlined here.
tl;dr:On behalf of post-commit reviews, where comments are addressed in follow up PRs. Developers can iterate faster, pull requests are kept small, code reviewer can batch review, along with cons and considerations.