20,000 fewer lines of code, faster compile / deploy times, significantly less interfacing / translation between "their" types and "their" apis, and a much better control over types and structure across our codebase b/c we didn't need "their" types and structure anywhere. It had crept everywhere.

It's just faster, cleaner, and easier in a few cases to do precisely what you need right now, rather than anticipate a million things you might need and refactor your code to adopt a given "solution".