Bruh, 5 years around here and you still think a sha256 ASIC could just mine scrypt just like that? ASICs are not GPUs, if you can't mine bitcoin or the two lame shitcoins cash and sv then there is nothing left to mine with them, recycling is the only thing they are good for! Look what happened after ETh went POS, all those video cards are almost losing money while mining, the same will happen here, instead of 7 cents per th/s a day you will be making 0.07 cents! as in $0.0007.
Oh my bad Im not a mining guru so i thought it can be possible . But even its mined out all supplied its their choice what to do on those equipment, maybe continue using it on bitcoin for the transactions fee. Probably there are ways how to remedy those unused equipment if that event happened. Prices will definitely go down due to this, but continuing the processing of transaction could increase their fees even without block reward for mining. Im just assuming that they could shift to other coins for the sake of mining.