Comment by jimbokun

I would collapse the senior engineer and architect roles into a single role and only hire people capable of doing both.

Owning the modules requires understanding the overall architecture and how the module’s API needs to fit into it, when a new module is required, when the architecture needs to change, and how to pragmatically migrate from one design to another in a live system.

All of that is easier if everyone is capable of operating at any level from overall architecture to micro optimizations.