Memory, in general, is cheap. Fast memory is not. If the memory parameters are large with scrypt, an ASIC could be built using cheap memory with a smaller amount of processing units (or slower/cheaper ones). The LTC scrypt design seems to be in a very reasonable range where lots of chips can be used, but each requires a reasonably-sized amount of expensive memory and fast buses to keep up. It's difficult to say how it will/would have played out when/if ASICs are designed for the LTC scrypt algorithm. But for now, GPUs being in the sweet spot could only be a good thing imo, botnet coins are no fun.