I never understood why CR choose CryEngine. Yes, it can Single Player games make look beautiful, but when it comes to Multiplayer, it never really could compete with Unreal Engine. Just look how much work RSI has to do, to get the netcode working - and so far, they still are limited to 24 players. In addition, the requirements of the CryEngine have always been high, the FPS drops and a lot of other performance proble…
https://starcitizentracker.github.io/
As you can see, development has stalled and very little progress is being made.
To answer your question: they chose a game engine to create shiny demos and carefully crafted videos. They have no intention of releasing a fully playable game. They just need to keep the hype going to keep selling virtual spaceships and virtual land.