Looks like Jim Parsons was the one who pulled the plug by not wanting to continue. I guess he wants to devote more time to appear in Zach Braff movies.
It's also fucked how this would be the first thing that would come up if anyone were to ever google Big Bang Theory Cinematic Universe
I'm going to marathon this show tomorrow. Starting with Season 1, Episode 1. Won't be getting out of my pajamas. So. Good.