Remember this game is only 2.5 months old. Most people don’t have a 60 plus a mid level or higher alt (some do, but most don’t). Give it a couple of more months and there will be many more mid levels running around again looking for groups. Level 60 is easy to find groups right now.
And the capital cities can seem lowly populated with players but that’s because it’s not retail. People don’t just afk in the cities waiting to teleport into a que…instead they’re actually out in the world doing stuff.
There are a lot of guilds on Felstriker with hundreds of players in them. I think people just have the retail mentality and need to relax a bit. The AH will pick up eventually. I always see peeps running around every zone from both factions. It’s not a zoo, but I like it the way it is.