Id say it depends on the complexity of your game and features you plan to use. I have a 7 year old scenekit game i just started to port over to realitykit for learning reasons and i keep hitting wall after wall.
i have a rockband clone with a 3d selection menu. This menu can have 10s of thousands of songs. Scenekit handled this no problem but in reality kit i cant get the same performance and i havent even loaded textures like cover art. just learned that it doesnt do material instancing so each object is a draw call. I spent two days trying to find out how to do it
then there is swiftui. As soon as i add a couple of textviews on top of my scene cpu usage spikes even when idle. Scenekit has spritekit overlays that can do very complex rendering with little overhead.
lastly i cant wrap my head around changing scenes. Scenekit scene presentation and transitions are easy to understand, with realitykit seems like i need to empty the scene and repopulate it Losing my music menu state and having to reload all the assets again. With scenekit i can elegantly transition back to the selection menu just as i left it.
i wouldnt worry about a game in scenekit breaking in future OSs. Realitykit has a long way to go and imo scenekit is way more flexible. Im quite shocked how slowly it was progressed. scenekit matured just a couple of years after introduction.
