That abstraction is another layer though. And additional layers are additional complexity. So, if you add another layer, the software is less simple than before

That abstraction is another layer though. And additional layers are additional complexity. So, if you add another layer, the software is less simple than before. You might need to have caching in your software. I don't doubt that. But there's simply no way it makes the software more simple except if you assume some unfortunate starting point where you could get rid of any high-complex performance optimizations in your existing code by replacing them with a more simple cache solution. But then the statement should be "refactoring makes your code simpler".