Knower here.
1. Runescape's balance tries to keep content relevant at all times. No matter what you're doing, you're getting a least something out of it. Even dead shit like trouble brewing which they refuse to bring up to the standards in 2025 is needed for an achievement diary step.
2. Runescape gives you micro goals for everything, which means the game is on like 8 constant treadmills at once. The game tries to avoid you grinding in one area for too long by giving you different subgoals to complete.

By the way, clue scrolls tie into both perfectly and if you want unlimited stackable clues you're stupid and shouldn't be able to vote.