Um, CS is totally about performance. Frigging P vs NP is about performance. Sure, there's a part that deals with computability and the halting problem, but I'm not sure Haskell is especially useful for studying that either! It can't even express the notion of "dovetailing over all possible programs" very easily :-)

Out of curiosity, what kind of CS do you mostly work with? If it falls under the umbrella of Curry-Howard, then sure, I agree with you. But CS has tons of other areas like graphics, crypto, AI... The impact of Curry-Howard related ideas on these areas has been disappointingly small, IMO.