It might be worth playing back some history here and looking at "intent" from a development perspective.
Back in 2012/13 CryEngine was a fairly decent FPS engine that allowed linked levels, had a good SDK with decent enough tools, a great rendering engine and was being actively worked on and improved as new features were being added to DirectX e.g. tessellation in DX11 and POM (Parallax Occlusion Mapping).
The levels you could produce with CryEngine were pretty large compared to most FPS engines (IDx, the COD versions of IDx, Unreal etc.), but it had major limitations, which a few days worth of serious investigation should uncover. Namely texture streaming going very funky away from the grid origin, plus positional rounding errors and ergo physics. Most of these were due to the 32bit coord system being used at the time.
It's also worth bearing in mind that a 32bit coord system doesn't give you a lot of room in the simulation arena, as the map area let's say for modern jet combat will have you detecting targets at say 60miles, using BVR weapons tactics (Beyond Visual Range) from detection down to visual range (<10 miles) and dogfighting from then on. The most you can stretch CryEngine to out of the box is about 20miles. Merging will happen very quickly in a box that size. Also if you want very high levels of detail you can "fool" the coord system by making everything oversized, but in scale with each other, but you shrink the world coord system even further by doing that (to say the same sort of size as the Arena Commander).
Now you could say a developer, who is unfamiliar with CryEngine and looking for an engine to develop a new game that has small arenas (<5mile cube), could and probably would come across the SDK, download it for free and without actually trying that hard, think "yeah this has all the shiny stuff gamers like and I can make a product with it". In fact if you look at the CryEngine development forums, it is littered with folks who do exactly that and some of the demos and creations look fantastic, but 99.9% don't end up as products.
If you were looking at said CryEngine as a flight or space sim developer then you might try and load in some terrain and try a few hacks to get a decent sized map, but ultimately you end up looking at coding a great deal i.e. you need a 64bit (double float) world coords plus all the dependant baggage in the rest of the engine that will have to be "fixed" as a result. What will be needed therefore is almost a new engine with retention of some areas like rendering, light and shading routines, POM etc. This is where I was personally when looking at a possible successor to a commercially and technically successful modern combat flight sim in 2012/13.
Here's the stinger though:
If you were say embedded or involved with CryTek/CryEngine at a corporate/professional development level during 2012/13, then you would either have to be a complete idiot or wilfully negligent in believing you could produce a large scale flight or space sim, without a ground up re-write of CryEngine.
A day's worth of due diligence with the SDK would easily give you a list of project workstreams that would need completion just to get a decent BVR to merge play arena going, let alone one where you want GTA meets Elite Dangerous meets Eve Online.
The sad thing is the folk who have invested $300million+ in this fantasy, have probably given enough funding to develop such an engine, provided they could sit on their impatience for a decade or so and have no playable demo or product. It appears however that rather than getting the engine and hence the product, they have invested in, they have instead had delivered one of the most successful "investment" generation schemes since Madoff's i.e. a large proportion of the $300million+ looks like it has been generating the $300million+ and not the actual product.
Full disclosure: I nearly kickstarted SC at the same time as I kickstarted Elite Dangerous and off of the back of videos back then by Jingles and Jester814. Then I learned it was based on CryEngine and backed immediately out of there, knowing that SC would need a new engine as complex as COBRA/Stellarforge or VU2 (the engine in the product I produced), both of which had/have been in development since the early 1990's and you could say arguably still don't realise their full potential, but are the best there is currently.