Easy. Outsourcings general return is something along the line of:

Cost Saving = .5X-R

Where: .4 is the factor that given programmers are cheaper. (So I'm assuming that your third world Programmer is half the price of your first world one) X is the total number of hours / days for the project *Note the implicit assumption here that all programmers are created equal) R is the risk factor. Harder communication, Cultural barriers, etc.

So for smaller values of X (say when you're using django not php) - then your expected return goes down. (And the overall influence of the Risk factor goes up - namely it could be cheaper keeping it first world)

A good explanation on why it is harder to outsource Django or RoR development is because it's so close to outsourcing the conception of the application. There are things you want to do in-house.

Uh, sure it does, near the end.

Some bean counters will be tempted to take it a step further. Why not outsource Django and Ruby On Rails work to low skilled low price developers? Its not worth the risk.