It is beneficial to keep in mind that evolution is not a directed process. [Edit: Not naturally, anyway. Domestication is human directed evolutionary forces. It is acting on humanity. Prison is culling force on human evolution, for example, today.] It isn't directional. We aren't progressing towards a goal in evolutionary terms. It's just survival to breed, which is dependent on continually varying conditions, and in fact evolution can oscillate back and forth if evolutionary pressures do.

"... the cataclysm that immediately preceded this emergence of civilization sharpened the collective intellect of the gene pool that survived it."

What is observed is that H. sapiens cranial capacity - brain size - has markedly decreased. Individual merit and intelligence is far more important in a non-social species like H. neanderthalensis than a eusocial species like H. sapiens. It seems to me that survival became higher for folks more willing to obey overlords in the conditions we have recently experienced as a species lately, and we observe that Neanderthals are extinct, despite their ~20% larger brains than we possess today. Cro Magnons, who immediately proceeded Neanderthals, and are our ancestors, had larger brains than Neanderthals.

Our ancestors were smarter than us, but that made society less controllable by overlords, and decreased societies' ability to wage war, as one potential reason for this decline in intelligence.

"... if we ceased to evolve significantly as a species..."

This is not the case. Evolutionary pressures remain in effect, they just vary continuously, and we don't necessarily know what they are. It is also not generally grasped that sometimes evolution happens in bulk, when cataclysm strikes. There is a tension between gradualist forces and catastrophic forces. Long term trends have effects that are suddenly countered, strengthened, or ignored by sudden and dramatic events like pandemics, geological, or political upheavals.

In biology, population spikes are a well noted phenomenon. Populations just don't rise exponentially to a plateau, and then remain at that higher level. When there's an exponential rise, there is inevitably an existential plummet. I sadly am confident this is something humanity will - again - experience, given our dramatic increase.

Genetic engineering and technology will present new evolutionary forces, and much of how that will impact humanity and life itself remains unclear to me. Once we escape Earth's corral, the limitless potential diversity of life will be unleashed completely, and wonders will never cease.

But, first we have to break free.

Thanks!