Each land has explicit areas of land left for future development , as someone who has pored over very detailed plans for this land and the absence of other possible explanation of why the theatre was place where it is, and grading being the way it is in the space left, it is a helpful confirmation of other info. Remember we are not seeing plans for each project on equal terms, we just got lucky one Monsters plan said future development.
anyway for those who want to speculation, I did actually tweet about this and it's dimensions a while back