> Couldn't a single coder (or a small team) help an organization get some competitive advantage when it comes to tools. Or even programming languages?

Sort of, but:

1) Knowing what to build requires deep knowledge of that the other engineers in your company are struggling with. Figuring this out requires a lot of time spent meeting with people and doing other things that would be considered more management than coding.

2) If the thing you build is good, it's going to start getting a ton of feature requests. Your company will decide that it's worth investing in, and suddenly you're either managing a team or somebody else is managing you and running "your" project.