There's one, fairly substantial, thing that hammers in the whole "what you see isn't IC", and that is the wormhole systems map.
In-game, until CCP disabled it, it was possible to map, the position of a wormhole system, using distances from POS towers. This showed the systems as being another cluster of systems, several lightyears to the south east.
A core of C6, surrounded by C5, then C4, with C3,2,1 being ever outwards to the periphery of the cluster of wormhole systems.
This is also repeated through examining the static eve data export, which has the universal co-ordinates of all the star systems. Again, same pattern of wormholes being in a tight cluster.
Except, according to CCP devs, all the J123 numbers used by wormhole systems refer to entries in a RL astronomy catalogue of something (quasars?), and they are scattered all over the universe, and their spatial relationship with each other bears no resemblance to what is seen ingame.
What you see ingame, is 'just a game' and not what you'd "see" IC.