@richpuchalsky I don't agree, on a couple of levels.
In general, I'm not sure I accept the link between "what makes for dramatic fiction" and "what I'd like the real world to actually contain".
In the context of the Culture universe, I think Banks emphasises that 99.99% of Culture citizens are perfectly fine without continuous fights against power. It's the outliers that make up Contact.
I think Banks approaches the grimdark point fairly directly at least once in-universe. In 'State of the Art', the character of Dervley Linter argues that late C20th Earth is more alive than the Culture because grimdark. The character of Diziet Sma (who is one of the Contact outliers who needs more fight than the average Culture citizen) treats him as being absolutely off his rocker. Their ship Mind pretty much concurs, but holds true to the principle that Linter is individually free to make dumb choices.