It is not only about development costs, but also about hosting costs. As a rule of thumb, when running an MMOG you won't have your own servers in your own office, but will rent them (apiece or as a part of the cloud) from an ISP/CSP. And then it is not about "what you'd like to have", but rather about "what they have". You may find a provider with GPUs (though they're going to be damn expensive), but with ASIC - no way (by definition, as ISPs are only dealing with commodity stuff). Hosting with FPGAs might exist in theory, but I've never heard of it. Of course, there are also colo options where you can host pretty much your own servers, but they're usually too much headache to deal with - and too expensive too :-(.