There are cases where the tradeoffs don't involve the actual codebase. For instance, there are certainly many developers who are 3x faster than the average dev

There are cases where the tradeoffs don't involve the actual codebase. For instance, there are certainly many developers who are 3x faster than the average developer simply as the result of having enough experience and/or skill to know which tools and/or approaches are optimal for a large subset of the kinds of problems they encounter in their typical work, such as a developer familiar with a particular ecosystem accomplishing some task in 10 minutes by knowing which library and which function to use, and how, whereas another might take hours (or days) to accomplish the same task since they have to figure out what tools are even available to solve an issue and how to use them, or worse (sometimes), rolling their own solution where a library implementing the functionality already exists. The tradeoff here is simply that it will be harder to find such developers, and they'll generally want higher compensation, but their work will not degrade the quality of the codebase, quite the opposite.