Well, I think basically what it boils down to is that DS9 is a bit of a transition between the TNG/Voyager style (episodic and basically sort of "wholesome" overall), which tends to feel really dated now, and the grittier, somewhat edgier sensibility that tends to be the norm these days.
It still revisits a lot of Star Trek clichés shared by the other shows of its era, and it's probably derivative of B5 as a concept, but it also had a lot of really good writers and actors working on it.
So it has aged much better than the other shows of its era and can be really rewarding when people revisit it, or pick it up for the first time on DVD or Netflix or whatever.
I'm not sure that equates to gaining in "popularity" at all in the standard sense, since the number of people we are talking about must be pretty small compared to the number of people who originally watched the show when it was on the air (ratings were always good or not bad for a show of its type, just not amazing like TNG's).
What it probably means is moreso that it is simply a good enough show that it will retain a bit of a cult following and always be worth watching.
Personally I haven't been watching it at all lately, but I look forward to revisiting it again at some point. It's one of my favorite shows.
My question is, had DS9 come on the air a decade or more later than it did, do you think it would have achieved a higher degree of success? And do you think more Star Trek fans are embracing DS9 now?
On this particular point, it's hard to really talk about a hypothetical.
On the other hand, one thing I enjoy about DS9 is that it was a bit ahead of its time. As far as the issues addressed, it *feels* like a show made in the post-9/11 world, when actually it predates that. You can also see that it was a bit of a creative crucible for certain things that some of the writers did later, especially Ron Moore's take on BSG.
So, I don't know... sometimes it's ok for a show to just be a bit of an under-appreciated gem. One reason DS9 is so good at times is that it was flying a bit under the radar and the studio cared about it less. I'm pretty happy it is what it is, and it doesn't really bother me that it probably never got the attention it deserved.