The fact that copyleft only kicks in when derivatives are distributed(GPL) or served(AGPL) indeed renders unviable selling copies of software. But I don't see how you could enable usage licensing without compromising most user "freedoms". This is certainly what "OSS-NC" would do, in contrast to even AGPL's copyleft. Instead, I think we would do better shifting the paradigm to the "pay per patch" model.