I’m not sure either. I think arch used to be one of the less popular distros (because of the more involved install process, solved now by the arch-based distros with friendly installers), despite having some of the best features, so it required more “evangelism”, that’s unecessary now. Arch-based distros are now some of the most popular ones, so its not necessary.
Others have commented on why its so great, but the AUR + Rolling releases + stability means that arch is one of the “stable end states”. You might hop around a lot, but its one of the ones you end up landing on, and have no reason to change from.
George jetson house, what they thought the future would look like in 1960: