These are the last time I read a forum post by a Dev on here. Those win% are based on top 1% data and they use them to adjust accordingly. If they see people quitting like this in the upper ranks, then they may do something. If you ain’t legend, or close to it, your influence on the factoring data is nil.
Outside of Warrior, most of the other 9 classes Questline decks are barely hitting 50% in the last 7 days alone. Overall, Pirate Warrior is the only Questline deck not experiencing regular declines in win%.