the culture Minds are intentionally designed with personalities (for lack of a better term) suited for their intended functions that keep them interested in/involved with base reality and their responsibilities there. there was a bit about how "perfect" Minds created without such proclivities will basically fuck off to a higher plane of existence asap. of course the culture Minds know this, they're the ones designing and building new Minds after all, and some decide that they'd like to see what's on the other side of the veil themself and that's allowed, but most are content running their ships and orbitals and whatnot