No, we really do. You simply punted on addressing what "multiple vendors" means given platform lock-in, and how that relates to traditional geographic definitions of a market.

The geographic model is based on the obvious notion that it's unreasonable to expect people to simply pack up and move to a different city to get access to a different vendor.

Given the amount of lock-in inherent in these platforms, it seems pretty clear that people can't simply drop their current platform and switch to another one just to access to a different vendor.