My favourite type of dismissal is: "X is a stupid idea that nobody asked for and it will never even work. Besides we already have Y[1], so this is nothing new.

My favourite type of dismissal is: "X is a stupid idea that nobody asked for and it will never even work. Besides we already have Y[1], so this is nothing new." [1] Where Y is some product that foreshadows the functionality of X and is already successful among some set of users, although has some incidental limitations that prevent its growth