Earlier quoted context omitted.
While I understand that looseness of your "common law" phrase, it's precisely the newness of the field that leads us to the lack of historical precedence (ie "common law"). So I would argue that we don't need "common law", we need "actual law". The problem is that "law" is a subject that is very, very specific. Don't want them yo sell "your data" - well then first you need to define what data is "yours" and what is "…
I'm not sure, IANAL but I would say that much of what a EULA or ToS covers is not that novel, companies skate by on technicalities, and a nontrivial portion of a typical agreement may even already be invalid but lacks case law. If companies weren't worried this might be true they wouldn't need the severability clauses. For example, disassembling or repairing items you paid for or duplicating legally owned copyrighted…
True in more than one way; owning copyright to your works and being able to refuse/get paid for commercial distribution was a right well established, but a sprinkle of right technology and suddenly they can charge people to copy your work on demand with minor modifications for your own commercial use (while you get nothing).