Has it always been like this or...?

[Viridiana]

Step 1: New players come to forums to complain that queue times are way too long. That Devs need to add incentives to bring back vets.
Step 2: SE obliges. They create Tome bonuses to encourage vets to repeat old content.

Here's the thing, though. The Roulette bonus is not there to help vets. It's there to help new players. Speaking specifically of the Low, Trial, and Story Roulettes. Similarly, the cutscenes in the Story dungeons are there for the new players. If you're going to participate in a Roulette that's designed to help new players, why would you simultaneously expect them to forgo the rest of what's there to benefit them?