Duplicate code is one of the biggest near-non-problems programmers waste a ton of time trying to address.
Sure, duplication isn't a goal, but DRY shouldn't hold back work as long as it has no meaningful consequence on performance. In some cases, duplication is a good thing, but your average programmer will address duplication by making a routing more complicated and further away from where it's being used. This is often a mistake.
Worse yet is when programmers DRY up tests. Tests are the worst place to be applying DRY. The point of testing isn't to write an entirely new application on top of your actual application. If you're DRYing up your tests a lot, you're probably writing a second application and should probably stop doing that.
Sure, duplication isn't a goal, but DRY shouldn't hold back work as long as it has no meaningful consequence on performance. In some cases, duplication is a good thing, but your average programmer will address duplication by making a routing more complicated and further away from where it's being used. This is often a mistake.
Worse yet is when programmers DRY up tests. Tests are the worst place to be applying DRY. The point of testing isn't to write an entirely new application on top of your actual application. If you're DRYing up your tests a lot, you're probably writing a second application and should probably stop doing that.