WCW's ticket prices were always quite cheap, certainly cheaper than WWF's. For the Dome show, it was also a matter of prestige since Turner executives were going to be attending, and obviously WWF and Austin had recently turned around the war after a long time of losing. I wouldn't be surprised if a bunch of the tickets sold in the last few days were discounted.
AEW would also have quite cheap tickets, which explains why there have been far more highly attended AEW shows that did not reach the $1 million mark. But recently, I think they have felt confident enough to increase their ticket prices, and attendance hasn't suffered so a good decision. Don't think it comes close to Raw and Smackdown ticket prices, but AEW's brand is nowhere near strong yet to command that.