Easy to forget that “fittest” is only relevant to the environment/context you are living in - if intelligence does not make you “fitter” for that then it will probably disappear.
Many animals have no need for intelligence/generality since they have a very limited behavioral niche (e.g. herbivores, crocodiles, sharks), so it wouldn't have evolved in the first place, but even for those that do the benefit has to outweigh the cost.
If every animal was a generalist they they'd all be in competition with each other, so I'd expect if you ran simulations you'd find that an ecosystem full of species that don't compete head-on is more stable, and therefore likely to result.
Bob: It's about the survival of the fittest.
Alice: Fittest with respect to what?
Bob: Survival.
So, survival of the fittest to survive, or what survives, survives.
It is utterly banal, but in popular culture, it has been "elevated" into a deepity.
For me survival of the fittest just means that with high probability those genes will survive who have a high probability to survive in an evolutionary setting. Is this trivial? In this wording it is trivial. But it can be useful. (And also it is not that trivial in a different wording. Just like other theorems, e.g. the theorem about the perpendicular bisectors of a triangle's sides. If a point O is equal distance from A and B and B and C then it is equal distance from A and C. Tautology, circular, assumption, name it what you want, it's math.)
It's almost a circular/tautological description ("survival of the survivors"), but "fittest" does at least allude to why some survive better than others (better adapted to prevailing environment), as well as the fact ("fitt-EST" vs "fit") that it's a competition for limited resources. Fitness is a matter of degree.