Alliance raids have no business being a relic step.

[Arkevorkhat]

I hate to be cynical, however I suspect it's because they know very little in the way of new content is coming. Therefore, they're arbitrarily trying to prolong the lifespan, especially for players who return to the game as Endwalker looms closer.

Honestly, I'd be inclined to say that such "cynicism" is warranted, after all, SE is responsible to their shareholders above all else. The issue is that they failed to account for the precedent they've set with previous content; generally, the rewards from a duty are fairly closely tied to the difficulty of that duty. I'd place DR at about the same difficulty level as Emerald Extreme, but where EmEX gave both a mount and semi-casual players' BiS weapons, DR gives some zhuzhed up Exarchic gear and an extremely rare chance at other rewards.