We all know Bitmain is currently mining with the machines before they open them up to the public. The real hurt would to do random forks before we catch wind of Asics coming out.
If you fork after it just hurts the miners albeit Bitmain's profit from selling used goods.
No, they would be pretty badly hurt in the medium/long term. From now on everyone (coins) will watch for big hash-rate increases indicating hidden new ASICs on them. Hopefully they (the coins) will prepare for that.
ETH fork will deliver the message of a giant anti-ASIC wave. They will think twice before investing in developing new ASICs for any algo. End of business model to me.