You could spend 15 years cutting every corner imaginable as a self-professed genius 1-man engineering team until everything becomes unsustainable, feature work is impossible due to frequent fires, the business is faltering, and you can't even understand your own code any longer. Then, quit as soon as a new hire comes in so you can't be held accountable for your quagmire by other engineers. I don't really understand why someone would do this, but I recently got to see it first hand. ;)
Damn 15 years is a long time. I think the oldest ball of unmaintainable spaghetti code I saw was 3 years old and it was almost impossible to add or change anything. None of the developers who worked on it and had the most knowledge of it could explain how it worked, not even at a high level. Like they barely understood it better than non-tech end users.
