RE: How do they make money?
By charging to use the network ? The key bit is OPEN, not FREE. You make calls, you pay. You use data, you pay. Get the idea ?
What the networks over there like is being able to control what you do and what you do it with - ie you get phones with ONLY the services/software they like because they can charge more for it that way.
One example that comes to mind. Supposing someone comes up with a nifty bit of software that can download and display maps and satellite images - including of exactly where you are stood if you have a GPS available. On an open network, you "just use it" and pay your network for the data transferred. On a closed network, you only get to use it on the networks terms - typically by paying for some form of premium services package at many times the price of the data transfer.
Another example, on an open network you can use a phone as a 'modem' and have internet connectivity for your laptop wherever you are. The networks don't like that as they'd rather you bought a separate data tariff for the laptop (thus paying them two lots of monthly 'line charges') - and so the phones they allow you to use on the network have the 'modem' functionality disabled or removed (yes, I know for a fact that they did this with the Treo 650).
The networks can still make money if they price their services right - but without the open network clause they effectively have a duopoly (in many places monopoly) and can charge exactly what they want, for the service THEY want to have available.