I have resisted posting in this thread as the off-line mode is not a big issue for me. I have good internet connection and no problem with the online game. I won't express an opinion on Frontier's decision or the manner of its announcement which I know have got so many people angry. The anger may be justified (although the content of some of the posts may not be!) but I want to speculate on the nature of an off-line option if one could be created. (Sorry if this has been said, I haven't been through all 400 posts!)
My point is that ED offline would not be the game we expect to be seeing after 16th December.
Even with big hard drives I don't think the 400 billion star galaxy could be held on a local system. We would be playing a subset of the full game, possibly no bigger than the volume of space we have now or even the pill we had in Beta 2. The bulletin board missions would be limited in variety and would begin to get a bit same-y after a while. The economy could not be dynamically active, except in a very limited way and it might be necessary to have random elements generated within it to avoid it becoming entirely predictable. The political situation, similarly, would be fairly static, although the game could contain some pre-generated scenarios which the player could get involved in. The chances of including walk-around-your ship or land-on-planets modules would be slim.
In other words, the game might become stale and predictable which is the last thing any of us would want.
I am 61 years old, I played the original BBC version and I said when I joined the Beta that ED would probably be the last significant computer game purchase I would make. I don't know how many years of playing I have left (I bought the lifetime expansion pass, but I won't ask for a refund if I drop dead tomorrow!) but I want to know that whenever I stop there was more out there which I never saw. If I have to pay a subscription to keep the servers running until then, I will.
I sympathise with those of you who feel you have been cheated out of something you were promised, but it may be that you won't see a true off-line version until our desktop computers are all equipped with quantum processors, programmed with David Braben's personality matrix and superfast ultra-broadband (or whatever they call the next stage) is everywhere.