How about the way Haiku is going?
http://www.haiku-os.org/They set up a corporation to manage donations and trademarks, the OS is available for free, and the contributing coders are mostly working for free.
The donations go to attending opensource events and hosting coding sessions as well as putting some money aside for hiring programmers to work on specific items on a contractual basis.
In addition, they have been part of Google's Summer of Code for the last several years and have had interested students work on things ranging from internationalization to porting Webkit to the OS.
So yeah, there's more than two ways to go about this type of thing. The Haiku devs are doing it in their spare time out of passion more than anything. I guess the MorphOS guys want to get paid a little. Both are valid approaches and if they want to get paid, more power to 'em!