Right now they do have a leader (Vereesa) and an organization that's working towards unite them. They found refuge in Dalaran, a city humans shared with them for 2,000 years. A city that recently has returned its full support to the Alliance. A city that can be moved to wherever new place the high elves could start a new home in.
The fact that they share their new main city with humans and gnomes also helps with both their low numbers and they being grateful with the Alliance for supporting them.