It seems to be that Rocket League’s march onward must leave a few platforms behind namely Linux and macOS. Psyonix will roll out a new patch this coming March that will be the games final update for those 2 platforms. The patch will basically turn the game into an offline version of its current state as multiplayer and new mod support are going to be cut off. all local player content will remain intact. In a statement regarding the move, Psyonix had this to say.

There are of course ways to still play Rocket League for those who will be affected. Linux Users can run WINE and Mac users can use Boot Camp. Regardless it looks like we will be seeing some big shifts come to the game in the next few months and that will be interesting to see.