Put simply, humans need to be dirty. We literally need to have bacteria on our skin in order to be healthy. All of the handwashing and sanitizer we foist upon our children is meant well, but in reality we're actually doing as much long-term harm as we are short-term good. The fact is that we as a species evolved in a dirty environment - we didn't have soap or hand sanitizer 50,000 years ago!
The same type of side effects occur when a software development team doesn't work in an environment where they're allowed to get dirty. They aren't allowed to experiment. They aren't allowed to fail in small ways that allow the team to learn as they move along. Everything has to be perfect the first time, or it's considered a complete failure.
So, how well does that approach work? What are the side effects of sanitizing the development environment to remove all dirt? Innovation is stifled. Code becomes riddled with Technical Debt because there is fear of making the changes required to keep it clean. Eventually, it costs an increasing amount of time and thus money to maintain and extend the code and ultimately a complete rewrite is required.
Wouldn't it be less expensive and much more effective to allow teams to play in the dirt and find ways to improve the software in smaller ways over time? Yes, there will be occasions where the small experiments won't work. Yes, there is a risk that some of the small changes will break other code. But, like the long term effect of allowing a child's immune system to be exposed to staph bacteria early in life, the rewards of keeping the code fresh and clean enough far outweigh these risks.
So, paradoxically, if people are empowered to get dirty, cleaner code will result.