[throwaway1777]

The idea is that entropy increases unless you put in energy. If you are specifically working to keep the code clean of course that’s possible. But entropy, bit rot, etc is the default state without any work being put in to combat it.

[Jtsummers]

And putting "energy" (people, time, money) into it isn't even enough on its own. I've seen plenty of 9-10 figure projects that were still suffering due to a lack of proper focus.