Honestly, the game will degrade like any unsupported game that's been out for six years. Even dedicated players like myself slowly lose interest. It's not that I don't like the game anymore. I still love it and it goes down as one of my favorite games of all time without question. It's just that at this point, the game doesn't hold anything really new for me. I've put in hundreds of hours and have modded the game to oblivion. I've used the mods of others as well. In the end, the game doesn't offer anything new for me.
Of course, the irony is that I keep looking for a new RTS game and I simply can't find any. Nothing I find compares to what I love about Sins. To be perfectly frank, I'm amazed I haven't seen anyone try to make their own Empire Tree.
Some day Ironclad'll probably realize SoaDA is not worth it, but whether or not they'll be able to get the capital for a Sins of a Solar Empire II is another thing. I personally thought their original idea of having a commander+heroes was cool and might have worked, but apparently it didn't so now it's just another MOBA with a smaller playerbase. They'd probably need a massive cash infusion just to make the updates to the engine, let alone the cost of development.
I can't recall off-hand if Dark Age is x64 or not. If it isn't, then that'll be a pain in and of itself because being x64 is the biggest thing about Sins II.
Heck, the only things that Sins II would really need IMO to be successful is an engine update. x64, good multi-threading, some better support for logic in buff chains, more powerful modifiers for modders, and more logical entity files. The new game would probably have a new faction and the combat balance system could do for some changes, but in general, the gameplay itself is solid. Sure, some other changes would be nice like mitigation working somewhat differently, but it doesn't need that.
Releasing a Sins II that was prettier, faster, and bigger would be absolutely amazing. I'd buy it the moment I heard of it.
In terms of gameplay, the single biggest thing I'd actually want is ironically not an addition, but a removal... I don't mind if Titans are a DLC in Sins II, but I don't want them stock. I don't like playing with Hero units in an RTS; I just don't.
So anyways, where will the game be in six months? More dead than it is now, leaving only super-dedicated players. It'll still make some money on Steam, but it'll be a trickle. Maybe in a couple years Ironclad will announce work has begun on Sins II. I hope they do... Sins is such a good game that was always marred by a sub-par engine.