If you say "they lost it because they developed something better" then how come WE lost all those good things just because we developed intelligence? Surely a fur covering and agility/precociousness doesn't interfere with that? Well, if you think about it, animals that have great speed and agility often have pretty specialized limbs to achieve those results. This means that they aren't very dextrous, that is to say, they aren't very flexible with what they can do. We don't have the agility, but our digits are much more dextrous than theirs, which means we can build and handle tools, etc. I think that qualifies as quite a big natural advantage. As far as the fur, well, some of us are still pretty hairy, but given removable clothes I think it's nicer to not have fur and be able to respond to temperature changes a little more efficiently.
"Well, if you think about it, animals that have great speed and agility often have pretty specialized limbs to achieve those results. This means that they aren't very dextrous, that is to say, they aren't very flexible with what they can do. We don't have the agility, but our digits are much more dextrous than theirs, which means we can build and handle tools, etc. I think that qualifies as quite a big natural advantage. As far as the fur, well, some of us are still pretty hairy, but given removable clothes I think it's nicer to not have fur and be able to respond to temperature changes a little more efficiently." We have the same number and density of follicles that Pan paniscus has, our hair is just finer and in most places, shorter.