Raiding in any game implicitly requires a heavy time investment by the player, even moreso for those aspiring to be bleeding edge. I doubt they knew what that even meant back when EQ was being developed 20 years ago but they certainly know now.
Personally, I was more of a tier 2-3 raider back in the day, often raiding content from the previous expansion or two. And even though I enjoyed some aspects of raiding, such as the actual boss fights themselves, developing/executing strategies, etc, there were other parts of it that were nearly unbearable. The endless waiting for players to show, mind-numbing trash to clear, bugs, etc, were downright painful.
I'm sure Pantheon will have it's share of end-game raids but they definitely seem to be hinting that the game will be more focused on smaller scale events.