Where there is a written power structure you can usually appeal to it and eventually get something done. Where there exists no written power structure at all, you're out of luck unless you can quickly figure out what the power structure is.
A written power structure is a low resolution map. It's not perfect, but it gives you some idea of where to start making sense of things. A flat organization is never actually flat, but it also has no guideposts at all to show you even the rough outlines of the real hierarchies.
Imo, that is argument for written structure. Written structure is easier to talk about openly talk about, reason about and fix. Unwritten structure is inferior consequence of its lack.
It's an example that Zizek has often given. The startup boss is more insidious than the old school boss because he's "just your pal". The traditional boss you can rebel against, in the startup you can't because duh, you have no boss, so what are you complaining about? It's a way to disguise power.
Another thing is that it's also a way to dodge responsibility, as you see in tech. When a Japanese company fucks something up, you'll often see CEOs take salary cuts and sincerely apologize in front of the public. No need in startup land, nobody was responsible.
So yes, the startups or orgs have to very explicitly lay down processes, otherwise the red flag is probably warranted.
https://respectfulleadership.substack.com/p/the-accidental-d...
I think a functional engineering decision process is more akin to a veto process. Someone, say Olivia in your example, would be tasked with selecting the language for the job and submitting the technical rationale for it and the relevant authorities (e.g. CTO or product owner) would sign off on the decision. They will normally have the power to approve or reject but not to impose certain solution. In a traditional hardware engineering, this is how it's done, where an engineer submits a design and it needs to be approved by relevant subject matter experts in various domains, such as material, thermal, structure, safety etc.
Good organizations allow interactions without too many gates. Which is what the good kind of flat refers to.