And, despite the talk about avoiding genetic enhancements, the occasional comment about 24th century little kids taking advanced mathematics indicate that something has been done to improve the average human's intellectual capacity.
Which could just be improvements in educational techniques. The thing about present-day schools is that they're not really designed to nurture and improve the mind, they're holdovers from a time when the goal was to shape children into compliant cogs in the industrial machine, their heads filled with rote facts and their capacity for critical thinking and inquisitiveness discouraged. There have been attempts to change that, but there's still a long way to go. In a culture whose school system was really designed to work with a child's natural desire to learn rather than against it, there would be a lot of improvement in the average person's intellectual performance.