All codebases are horrible after some years- that is the result of "please invest not time into this done project"- hotbugfixes piling to spots where they don't belong. The existence of this architecture corrosion is not something to be ashamed off. And everyone who reads in, can do so while refactoring those "if (input(isExoticEdgeCase)){...}" into some Filterclass of there own. My assumption is, that often management is in fear of being proven wrong, by some project coming alive. "This Project is not profitable, lets open source it." is a statement that can haunt you, if that very project comes alive and walks the earth for years to come. Coders and management united in fear of public embarrassment.