I think Google's enterprise pricing was targeted towards, say, a long-haul trucking company or a corporate GIS department where the viewers are just some managerial or analyst staff. In cases like that, if they charged the same rates as they did for CraigsPinSquare, they'd make a few pennies. Thus, the solution would be to discriminate pricing between high-volume consumer-facing usage and low-volume internal "enterprise" usage, especially since internal "enterprise" usage wouldn't give Google Maps much publicity.
Google decided that we fell in the "enterprise" bucket, and enterprise sales typically involves private negotiations with pricing. It's very possible that we got wildly different pricing than other companies.
We're still open to using Google products in general, but OSM is more fun.