If you have to pass data up and down, back-and-forth the chain and rely on mutation, sure, yes. That’s ball-of-yarn in a nutshell. There is such a thing as reducto ad absurdum in software.
Nevertheless I’ve found far more God classes that could be refactored into clean layers than the other way around. Specifically in the context of Rails style web app as GP is specially discussing. Batteries included doesn’t necessarily require large tangled God classes. One can just as well compose a series of layers into a strong default implementation that wraps complex behavior while allowing one to bail-out and recompose with necessary overrides, for example reasonable mocks in a test context.
Of course this could then allow one to isolate and test individual units easily, and circle back with an integration test of the overall component.
