No one can do fast prototypes with types, all they can do is convince themselves they are faster than they really are.
Having worked in both dynamically typed and statically typed software development shops, the statically typed programmers are considerably slower in general. Usually they only have 1/3 of the output as programmers who use dynamically typing. Statically typed programmers also tend to be much less ambitious in their projects in general.
They still think they are "fast programmers" but it's complete fiction.
