A 1070 should be able to handle pretty much everything below 4K. New cards are expensive because of their ability to do bitcoin and Nvidea controlling supply.
There has been attempt to ban bitcoin mining in China but it's an ongoing issue. Only way to end the issue is ban E-currency mining entirely worldwide which could massively decrease energy use. Negative part is it will irritate the owners of the coins and may cause legal issues.
The 2070 I have manages 4K in games adequately but the prices aren't going down very far without international government agreements.
It can not. I have a Acer ultrawide and it can not even have Battlefield 5 on good settings.