[Vraxx]

The system in place didn't do anything to protect the mod from being uploaded fraudulently. If I wanted a $0 price tag on my mod, I especially wouldn't want to spend time I could otherwise be working on my mod policing the store to make sure nobody is selling my mod. Fix that and you fix a lot of the issue.

[emodendroket]

That's a pretty nontrivial problem to solve technically.

[Vraxx]

Well, I guess the other issues listed here were nontrivial enough to make a solution unfeasible, or Valve probably wouldn't have backed out.