I think it is naive to belive that at some point DNN wouldn't be a chargable product. It has a way to go before that. But, in this business, the only way to measure the value of a product is the willingness of people to pay for it. As long as the product meets the needs of the customers, there really shouldn't be a problem. It is when it gets ridiculous like Vista where  the price increases and no real value is added to the product. That is when we should balk and not move forward. The problem with the open source model i find is every one reinvents the wheel and you lose cohesion in the code base. Look at DNN you can tell who worked on what because the styles are so dramatically different. This introduces alot of the little bugs that drive the core team crazy trying to fix. If you look at the modules you can find several ways of accomplishing the same thing. it has worked this far because we spend our free time tracking down the bugs and fixing them but, if this is a commercial product, these types of bugs would kill DNN. I really don't have a problem shelling out money for something that helps me accomplish a goal but, i won't if i have to spend a week or more gutting it and cleaning up the code to remove  errors.