Sadly that's the main problem in my opinion. As far as I know there are still some rare events which can bring players back but it has been stagnating for years now.
I owe some of my high school social life to the fact I could beat anyone there at aoe, so I made friends with some of the older kids by teaching them good builds.
Forever! Actually I recently found out that there's still an active (semi-)professional scene which blew my mind. Amazing game, I've started playing a lot again and thinking about hosting some LAN parties for it.
Last fall some friends and I tried to set up a LAN party with Age of Mythology. The networking code on the Windows 8-compatible version was truly terrible but it was still a blast to play. Wish we could have done Empires, too!
Also, right when Doom came out, I remember my dad setting it up on work computers after work, and he would play deathmatches against his coworkers Dave and Mike, and they'd let an 8-year-old me play! Such fun times.