You are missing something.
The RX480 is a new mid range gpu offering high end performance for a lot less money.
The GTX980 launched at around $550, this card is as fast as or slightly faster and it comes in at $200-$250.
The GTX980 is a fairly strong card, easily able to max anything at 1080P and able to run most games maxed or close to maxed at 1440P.
So you'll be getting that level of performance, with much lower tdp and much better efficiency for a lot less money.
AMD aren't competing with high end Pascal, they're opening the door to high level pc gaming at a much lower entry point.
If you want competition for the 1070/1080 you'll have to wait for Vega, which will be available towards October/November this year.