> Direct engineer -> engineer communication between teams is O(N^2) to organize things between N engineers.

This isn't true in my experience. I'd say it's more like a binary search than a fully-connected network. I talk to my immediate team first. If they can't help, I dig through the company-wide documentation and codebase, then message people who have done or considered something similar to what I'm trying to do; they either give me the information I need, or direct me to someone more likely to have it. Each hop gets me closer to an answer, and I typically end up having to talk to 1-3 engineers rather than the O(500) who work in my organization.

Part of the reason this works is because there are a handful of very senior engineers who have a good sense of what's going on across a big part of the company. Complex requests often get routed through one of these people, and they always seem to know who to talk to. I guess that's a form of hierarchy, but without the "command-and-control" aspect. I see it as an occasional escape hatch rather than a primary means of problem-solving.

I have to ask though: if a company built on engineering doesn’t empower its engineers to make product decisions, who can make them?

In my anecdotal experience, the “product” people generally have lesser context than the engineers, and often rely on engineers to do their jobs. The good ones make a serious effort to get at least a vague understanding of how the product works and are hungry to hear ideas on how to deliver more value.

However most PMs will not be this way. Their primary instinct is to interface with the product hierarchy and explain to engineers what the “higher ups” want. They exercise this power by vetoing ideas that don’t fit into this narrative, even if these ideas would improve the product. Engineers then mostly don’t really share everything that they’re working on with the apathetic PM; the motivated ones build things anyways risking rebukes while others will do just what product asks for.

The only scalable solution really, is to create processes and career paths for engineers who are inclined to product design to become PMs, or at least spend part of their time as PMs.

At Service Oriented B2B companies, there is another class of people who become excellent PMs: the Customer Service Managers, who have dealt with Customers and their issues, and have a deep understanding of the problems and frustrations faced by users of these systems.

It's not the only solution for building products. But you can still maintain dev autonomy. Instead of having senior team-members break apart work into story-sized pieces a system can be broken apart into smaller pieces. Devs can still be working towards a specific business goal, but they can own a larger portion of their work, and they can work with longer deadlines.

Also, I think dealing with those large scale issues is what separates a staff/principal dev from a senior dev.

This is where I think Apple does really well by having lots of small teams that each focus on a particular product area (Calendar, Remote Desktop, etc).

Teams have very limited scope in exchange for enormous autonomy. “Inmates run the asylum” as my former manager put it.