Yup. It's comparison bias. When all we have to compare to is each other, it skews our view of each other to be lower. Think of the worst player on the US olympics basketball team. He's the worst player. Every other player on the team is better than him. He's still an all-pro that's better at Basketball than 99.99999% of the world's population.
Same thing with our raid team. Even our worst raiders are far better than a good wow player.