Many people are happy to play for internet points, whether they're SO points, number of patches submitted, bugs fixed, or something else. I'd be really happy if performance was one of the games they can play.
It's not an either-or. Maybe the best long-term approach would be to write it in a high-level style favouring readability, productivity and adaptiveness, while also being conscious not to use features that could lead to performance problems. Maybe you'd write it in a compiled (native/efficient VM) language with garbage collection and be mindful of memory layout, instead of writing it in Rubyand then having to rewrite some parts in another generally faster language later. Then you also wouldn't have to have that "Ugh, now I need to bust out C++/C/Go/Whatever and rewrite that stuff... oh never mind it's probably fast enough" when you start to run into performance problems.
 More precisely an implementation of a language which is compiled...
 Though maybe Ruby is compiled in the canonical implementation, for all I know.