This implies that the cost of producing unprotected digital goods in general can only be covered by selling some non-digital good or service in conjunction with it.

My impression was you did not agree with this point and where simply bringing it up as a topic of conversation.

Clearly many individuals and companies do make a lot of money selling content. I simply feel that what's needed to keep that model working in the long term is more costly than the value of content it protects.

I was bringing it up as a topic of conversation, mostly in the hope that someone would argue against it convincingly, because if such an argument can be made, I'd like to hear it.