I agree with much of what you say. And I think it has a lot to do with the following 2 points (one of which is being addressed, but the other has not YET):
the prevalence of so many shit decks in the higher league matches... when they are comfortable that we have true peer to peer competition, then I think that will change (or show where all the abuse is happening).
the reward structure is heavily weighted to the top. While its better than it used to be, basically the top 16 decks get paid the most. I would think they need to re-work this concept in the future if they want to have more than 50 large decks competing for those 16 slots... Otherwise you are right, the game will go nowhere as the top 16 eventually wear down all other competition.