In an interview with Eurogamer, ID@Xbox Europe Boss Agostino Simonetta had once again stated that Microsoft have are ready to active cross-network play. This is already active in the Xbox One version of Rocket League and would simply need Sony to come to the party and work with Microsoft to make this happen for future releases. Sony are yet to comment on the matter.
Simonetta had the below to say:
Absolutely–we’re ready. Rocket League is the first game–and it is a heavily network-orientated game. Any title that wants to update their game to include cross-network play, any title that wants to launch soon and take advantage of that, we are ready.