How naive can you be? They don't need to compete with themselves (in the consumer space anyway) because their cards are still selling very well and they have huge market share.You guys are giving too much importance to the lack of competition.
Nvidia doesn't just compete with AMD, they compete with their own products.
I'm sure most people stay loyal to a brand, the people they'll sell 2070/80s to are those who have Maxwell and Pascal, so the fact that "there's no competition" doesn't apply.
Also, name a single industry that thrives without competition.