Depends on whether any of the people buying and rating it are actually new listeners, or if it's mostly just people who are already familiar with JoCo.
Right now, JC's song has 1,324 ratings, 1,314 of which are 5 stars. The ripoff has 1,472 ratings, 1,285 of which are 1 star. People are stepping up to bat for Jonathan Coulton. It just takes one person with media connections to step up to bat for this to get wide mainstream coverage. That's where the real upside for JC is.
Unfortunately, my only solid media contact works for a Newscorp company. It's time to think if any of you have news media contacts.
I also imagine there are a lot of Anons just looking for an excuse to rally against Fox/Newscorp. I'm not endorsing vigilantism, but Glee is one influential Anon away from wishing it had pulled its collective penis out of this hornets' nest and apologized before it felt the first sting. If the hive awakes, it's too late for apologies and Jonathan Coulton may be sucked into the media draft of Fox/Newscorp's supersonic pain train ride to Agonyville.
I don't see any situation where he makes retirement bank off of this, unless it turns out Fox actually used his recording. However, it's definitely within the realm of possibility that he comes out a few tens of kilobucks ahead on this if it gets picked up by mainstream media and/or some Anons use this as an excuse to go after Fox/Newscorp.