Also da hat Psyonix inzwischen mehr Informationen zu veröffentlicht (wenn auch nur auf Reddit).
https://www.reddit.com/r/RocketLeague/comments/etiih3/update_on_refunds_for_macos_and_linux_players/
"Regarding our decision to end support for macOS and Linux:
Rocket League is an evolving game, and part of that evolution is keeping our game client up to date with modern features. As part of that evolution, we'll be updating our Windows version from 32-bit to 64-bit later this year, as well as updating to DirectX 11 from DirectX 9.
There are multiple reasons for this change, but the primary one is that there are new types of content and features we'd like to develop, but cannot support on DirectX 9. This means when we fully release DX11 on Windows, we'll no longer support DX9 as it will be incompatible with future content.
Unfortunately, our macOS and Linux native clients depend on our DX9 implementation for their OpenGL renderer to function. When we stop supporting DX9, those clients stop working. To keep these versions functional, we would need to invest significant additional time and resources in a replacement rendering pipeline such as Metal on macOS or Vulkan/OpenGL4 on Linux. We'd also need to invest perpetual support to ensure new content and releases work as intended on those replacement pipelines.
The number of active players on macOS and Linux combined represents less than 0.3% of our active player base. Given that, we cannot justify the additional and ongoing investment in developing native clients for those platforms, especially when viable workarounds exist like Bootcamp or Wine to keep those users playing."