It's not just Coachella. AEG is one of the leading if not THE lead in global entertainment.
The own over 343 Venues across the world
They put on 25 Music Festivals yearly (including Coachella, Electric Forrest, Firefly, Hang Out Fest, New Orleans Jazz Fest, etc.)
They put on 15,000 Shows annually
They host more sports franchises than any other in the world
They build entertainment districts all over
They build, Hotels, Stadiums, Clubs, Theaters
If you've been to a show or a sporting event recently, AEG was most likely involved in some aspect.