Don't get hung up on the free as in beer. That aspect is a unique response to the
competitive and market environment in which free software has grown. It would
have been impossible for any of the rich environments to exist.
I started in computing when a single use piece of software cost $3-400, and many
paid willingly. Now that almost buys a machine reasonably well equipped, the profit
coming from very large volume of sales.
In VOIP, these people are selling their services. It's very easy to come underneath
the likes of Nortel and still make good money.