I think I agree that in some cases it makes sense to open source things and in some it doesn't. I think when you look at a site like Teambox it makes absolute sense to be an open source product.
To play devils advocate to your point though what about mysql, that's a downloadable product that makes it's money from commercial support or to a lesser extend tools like Phusion passenger. Most people don't pay for them for the thousands of Rails websites passenger hosts. However, for those larger enterprises it's much better to employ the experts for support.
The key is looking to see if you business fits exactly as you say.
To play devils advocate to your point though what about mysql, that's a downloadable product that makes it's money from commercial support or to a lesser extend tools like Phusion passenger. Most people don't pay for them for the thousands of Rails websites passenger hosts. However, for those larger enterprises it's much better to employ the experts for support.
The key is looking to see if you business fits exactly as you say.