> But working alone is critically important for all the pieces of the development process that aren't technical.

Sure, but good engineering happens with closed feedback loops. Even if you learn to check your own assumptions, users still need to be informed, documentation improved, subsystems integrated, new platforms supported.

Good engineering is a team sport.

So maybe you can turn a confusing stack trace into a patch on your own. Great. Tru success happens when you ship. And shipping to yourself is rarely interesting.