I think the problem with simple is that people that don't know what they are doing are too tempted to just copy the simple everywhere, not knowing when to stop.

Then when you reach the point where you need to change the simple to something more complex, you realize that there's 249 places where you need to change that simple thing, and management is unwilling to take that risk just to prevent potential problems down the road, so the simple thing slowly grows to 984 places, when a massive, massive incident happens, and suddenly it becomes the highest priority to fix. Joy.

In my experience, the _only_ time to make things complex is right from the start.