Kind of. ASICs aren't exactly super available, but the manufacturers are also players, so if the attack is severe enough to be an existential threat to Bitcoin,

Kind of. ASICs aren't exactly super available, but the manufacturers are also players, so if the attack is severe enough to be an existential threat to Bitcoin, I expect Bitmain (largest ASIC manufacturer) will fire up their unsold inventory which amounted to more than a billion dollars worth as of last year. Separate from the manufacturers, relatively easy courses of action I can see are buying hashing power from marketplaces like nicehash, and temporarily concentrating their machines on BTC and not mining BCH. This can only get you so much though since BTC hashrate dwarfs BCH hashrate.