The Culture is also very cautious about running high fidelity simulations for ethical reasons. Useful simulations approach the real in fidelity which makes them problematic to delete -- But they still do it.
If the Culture has Minds, why wouldn't other civilizations?
And why would Culture-esque Minds be superior to less-Culture-y Minds?
The Gzilt minds are specifically compared to culture minds and deemed to be comparable in capabilities.
Well, that's not really realistic. Maybe they are only pretending to be based on organics, but really aren't, and just put up a facade.
See underlying textual creepiness about "what exactly are the humans for?"
I.e. an inverted Matrix, with the humans kept in the physical
The thing hidden in plane sight is the has and has nots of the culture though. Some have processing power- and some must beg those with processing power to run all the things.