Its not a matter of how much work the Devs do or even how much money they have, its a matter of being sensible.
Sure make the entire system one instance but the game would have to generate the entire space of a system meaning instead of a few bytes of data you are talking MB or GB of data. Think about it, every NPC in every nav point, SSS, USS, RES and station, all their velocities, positions, current status, combat on every last player and NPC in the system. Talk about bandwidth cap and that's without even mentioning the computing power the end user would have to have.
Then add in the rotations of asteroid belts and stations which I think you'll find some are over 50km/s (much faster than the normal ship speed, we are placed in a relative speed instance when dropping into these).
You'd have a hyperspace loading time of minutes per system just to avoid a few seconds in individual loading screens.
Lest we not forget we are over a year into production, I just don't see this ever happening since if they were going to do it they may as well start from scratch and re-design all the core game mechanics.
Computers are faster but not everyone's are, limiting the game to those on 150mb broadband and £3000 gaming pc's isn't going to end well for a company that wants to remain in business. Its bad enough as it is now with players rubberbanding around the place!!!
Tl:dr Not gonna happen, loading everything per system is a bad idea.
Edit: Guys he isn't trolling since similar things happen with offline games like Skyrim/oblivion mods. He just fails to understand the technical background it would need to apply it to a server based game. It really is not as easy as flipping a switch or re-writing a coding line. Its probably about 5 people spending 6 months just to get it to work let alone optimising it so its playable.