Looking at the TV deal, they may require a massive up-front payment for the theme park rights too, perhaps $100m, and a minimum spend in the $500m range.
Only Disney/Universal can afford that, but given the current announced spending of Disney and that Universal can offer larger spaces/projects, it seems pretty clear where it'll go.
I think Tolkien's estate realizes that they do need to build out their IP. Looking at how GoT has filled a void in epic fantasy on TV and how many IPs are moving to theme parks (Potter, Nintendo, Star Wars, etc.), that space always was meant for LOTR.