It's not over until it's over....
From SIA developers regarding Bitmain Asics...
We prepared for something like this by adding an extra feature to the SC1. We can do a soft-fork that slightly changes the PoW algorithm which would invalidate the bitmain ASICs, but allow the SC1 units to continue working.
Let the games begin!
this means war! Oh, Goodie. Gets popcorn!

Is that mean obelisk will be a total useless even before they start shipping? Or there will be some times for obelisk to modify in order to mine the new POW algorithm?