When you can no longer get upgrades from starter zone quests, you don't expect them to raise cap on starter zone loot - you move on to more challenging content. The harder the content, the better the gear. If you are geared so well that WQs offer no upgrades, it's time to take on bigger challenges!
Broken Shore will offer more challenging quests and probably better gear for a bit. Meanwhile I am 880, raiding, tanking M+ 10s & 12s, but I still do WQs every day for artifact power. Because artifact power is the surest way to progress your character under the current model.