I do agree that elves definitely are not smarter than humans, but it might be because they don't understand much about human culture (in the first book I think they said they thought humans still have monarchs). But yeah I could tell Brant was a Neverseen from the moment he was introduced.
Also I think the Lost Cities are a more socialist/communist society (like with some aspects), since it doesn't specifically mention elves getting paid. And elves work because of a combination of the gnomes doing harder work, and elves not being able to handle guilt (so they would want to do work). So elves' birth fund come from the work that they do. Also a cool idea would be like elves would have to work off their birth fund, but that's a different idea.
Plus about the population thing remember that elves usually only have 1-2 children (because they think genes get weaker the more births someone has, another example elves aren't that smart), so the population doesn't really grow that fast even though there are infinite life spans
If there were, say, 10000 elves when the council was created 5000 years ago (around the time ancient egypt was unified), every elf had 2 children, and no one died, then there would be 1,500,000 elves today.
The text below is a spoiler.
Of course, there are only children in kotlc and some elves died, so the population probably is less.
Also please don't see this reply as rude (I know this is way later and you probably won't ever see it), I'm just answering these questions bc I want to.
