I'm actually laughing at myself while I'm typing this, because I used to think exactly that. To the point where I was THIS close to jumping off the bandwagon and leave ED for dead back during pre-release when "offline" was taken off the table.Make it a off-line single-player game and eliminate all the multi-player crap, including the 'balance' nonsense.
Now, however, I can't imagine myself playing it any other way that the way it is, hence my laughing at myself. I do know and understand the "why does everything have to be online these days" feeling, I feel that way myself most days, but for ED I happily make an exception. Besides, even if I DID decide I never wanted to play with anybody else ever again (ain't gonna happen), I still have Solo. There. No annoying humanses to bother me.
All of this to say: You already have single player. It's called Solo. As to the balancing, it would still be there, since FD would still be the one arbiter when it came to what you could earn/do in offline single player.