When that's the cultural norm, people adjust accordingly. Tools include liberal use of assertions, defensive tests, and most important, code reviews that catch and remove quirkiness.

It's a nice environment to work in. In addition to hastening Noogler onboarding, it also increases employee retention. If you are an expert in your project's codebase but get burned out, you can easily transfer to another project and be almost immediately productive.

Obviously, there's domain-specific knowledge that doesn't transfer easily or quickly from project to project. But that's quite different from self-inflicted code fragility; one's an asset and the other's a liability.