It simply means those people are more rare. Just look at Logain, Taim, Nynaeve, Alivia and Sharina ... These people are all modern Age and as gifted as any of the Forsaken. They all seem to be as intellectually gifted as well, the entire main cast are all a match for any of the Forsaken and I'm fairly certain in real life someone like Charlemagne or Queen Elizabeth or a dozen other major world leaders are an IQ match for any world leader of today.

Sure there are more people of genius IQ or extreme OP strength in a dramatically large population, but that doesn't mean those people cannot exist in a smaller population.