NumPy is not fast enough, that's the problem (http://technicaldiscovery.blogspot.com/2011/07/speeding-up-p...). In scientific applications, the code calling it is rarely the bottleneck-- if it is you might be doing something wrong. The biggest bottlenecks I encounter are a) computation and b) data serialization / deserialization (especially if a database of some kind is involved)
