Yes, there are other Christian music fests. I have been to other Christian music fests.
But Cornerstone, which is approaching its 29th (and last) occurrence, is different from those other music fests. I first attended Cornerstone in 2007, and it spoiled me for the other fests. I haven't been to a different one (even though Creation, Alive, and Ichthus are all closer to me geographically) since attending Cornerstone.
It's just not the same -- it serves a critical function in the American church. And after it disappears, I wonder what will take it place. Please, something take its place.