The line between a game and a sim will always be blurry and dependent on the individual. As you move from one to the other, all you get is an increasing probability that more people agree which it is.
If the SF series comes to an end, that's fine...it has had a pretty good run. But, from what I've seen of other sims, I have not seen anything that balances playability verses realism, combined with modability and variety of third party content of the SF series. Everyone talks a big game of how much other sims can do...yet, how large is the third party content of any air combat sims? There are some beautiful aircraft and cockpits out there for other sims...but how many? Any more than 10 for a particular sim?
I'm seriously asking...because from what I see, there isn't a whole lot.
Also, with increasing complexity and fidelity of a game engine, it also usually means increasing fidelity of the third party content to keep up. Which increases the time and effort involved. Just how many epic looking mods of various games have never made it out because the technology outstripped the modder's energy. Hell, we've seen it here with the Mig Alley mod, and that was what folks here admit is a slow advancing engine, and that was for a conflict that doesn't have a EM warfare enviroment.
In some ways, if the SF series comes to an end, I'll be happier about it.
It means that any future mods I make will always be compatible with the latest patch.