Originally Posted by
Arikara
They aren't, though. The Highborne split into the high elves, the nightborne, the naga, the satyr, and the Shendralar. None of these are part of the playable group of night elves. When you refer to Highborne, odds are that what you really mean to say is Blood Elves.
After the War of the Ancients, the Highborne very specifically split up into multiple different groups. The few that choose to stay with the long vigil group did not retain their Highborne status, did not practice arcane magic, and did not hold any pride in that heritage. They don't exist as part of that group, because they renounced their status and became commoners.