I spoke in a moment of frustration, it is not really that simple nor for that reason that we are going to include locales in the main scm extensions. Though sure, this thread sparked that debate, there were several issues to consider regarding loading, unloading, etc. .
Mostly, we don't want the scm to head down the slippery slope of feeling it needs to compete with the tcz in terms of modularity, size, etc, therefore diluting it's main goal of being self contained. Larger downloads are just part of that concept.