The longer you live, the less adaptable your species is. The more generations you can have in a shorter amount of time, the faster you can have beneficial mutations that help your species survive changing conditions.
I live near Yellowstone. There are seasonal hunting grounds the bison, which live a decade or two, won’t cross into. The wolves, meanwhile, don’t live long enough for the lesson to stick. So they continuously cross and get shot.
Humans erected an invisible barrier. The bison adapted where the wolves, arguably the more intelligent creature, did not, in part due to the latter’s short lifespan.
The best of both worlds would be a long-lived polygamous creature that’s constantly reproducing. Ecology, however, proscribes limits on that approach.