You can use Heroic to manage Epic Store games. It's not that hard to use on Linux. I rarely do it, but it's easy. I don't see why anything would prevent Linux users from playing it.

People who bought the game on steam can still play from there but also EG works on Linux (source: I play from Linux)

The industry just needs more, not Rocket League itself. They need to feel like they are missing out to change.