And to be fair, often times it is against the senior's judgement, but if off the critical path can be a decent gamble. The hubris of junior engineers accomplishes a lot.

Yes, it's true great developers can 'reinvent' things and do a great job of it, but the problem is that every line of code in a project is an efficiency drag forever moving forward. It always has to be maintained, updated, and managed by someone.

Developers should be measured by how many lines of great code they can delete, not how many lines of great code they create (<-- but don't take this literally of course, it's just making a point)