People don't play games because it's a "good" game, they play because it's "fun" and "accessible".
Or as I think of it, "Gamer's suck" ;-) (Kinda like lamenting that voters suck ...)
It's quite obvious over time that you see mobs running here and there to snatch up "the next big thing", whether X-Wing or Guildball. The stuff that stick longer than 6 months to a year? Those tend to be the actual good games.
I think the actual number of gamers who treasure involved and complex games that also require miniatures assembly and painting has grown only slightly over past decades. It's just that the overall number of gamers, period, has grown - and a larger chunk of those now prefer the "accessible" games. But they're coming from video games and cards, and not a model hobbyist side - so something with a strong IP and no painting like X-Wing is natural crack! Heck, I'm not a painter type, and if I was starting from scratch and all these pre-paints were an option? That's what I'd play!
Mini gamers are also dispersed among a dozen systems now, instead of the old unified under GW situation. So it seems like those who play the games we like are few and far between, when compared to the larger herds.
As I've seen from low points for Malifaux or Warmachine, all it take is a good release push ...a good intro product to draw them in. Taskforce was a nice idea towards that, I just don't think it was well executed (IMHO).
Back to the topic, I think DSC will be even more niche for most. Those models CANNOT be easy to build, they're expensive, and the rules are no doubt as tough as the DZC rules. So while it might balkanize further the "Naval/Sci Fi mini Gamers" , I don't see it dominating anything. If I'm wrong, I'll be extra sad - not just for Spartan, but because I *really* don't find anything appealing in the DZC fluff.