I think that's really unlikely on a large software project, or even a medium size one. Mature things usually get big enough that developers specialize in an area. Just as a random example I know a lot about, Unreal Engine has so many incredibly complicated and huge features that expecting even a project manager to know half the features is unlikely, and expecting that a single programmer could maintain it is wild.
You're also making the mistake of thinking developers are interchangeable, or that any given developer can know all of the tech stack. Again with the Unreal Engine example, how many developers understand animation, procedural generation, localization, high end 3d graphics, the math behind physics, gameplay systems, storage systems, consoles.. (I'm probably covering like 5% here)