Thimbleweed Park (or maybe Terrible Toybox) has a non-zero value now. Ron and Gary (and possibly other people and/or companies) own a slice of Thimbleweed Park. Ron and Gary and the investors spent time and money for their slice of TP. Their slice of TP generates current and future income from TP and other related stuff (merchandising and other, whatever these may be). If they wanted to sell the rights to it they could get a greater than zero value for it). So looking it financially-wise only you need to take this calculation into account. And these include a lot of parameters that you might not be considering.
There are other non-financial aspects of whether the project is a success or not. And I think that (possibly excluding Ron and Gary’s current bank account situation) the project has been a great success. I hope that the value that they generated into TP is going to pay off for them, and sooner rather than later.