"The thing is, Steem doesn't need to fork to keep going at all, it just has to keep going as it is and as long as witnesses keep the chain running, it runs."
Maybe. @steemit stake is substantial enough to control the witnesses, and if Tron has acquired @steemit's stake, which it appears it has, then Tron can replace extant witnesses with ones that support whatever Tron wants to do to the code.
In that event, for Steem to continue to operate as it heretofore has without changes to code Tron may seek, Steem will need to fork out @steemit stake, essentially becoming a new platform and token to enable legacy operations.
Thanks!