At a certain point (barring a technological revolution of some sort) we will probably run out of truly new questions of a certain type, dealing with the basics of the process. I've often said, without my tongue in my cheek, that I could probably take anybody of average intelligence from the "this is what we call a 'camera'" phase to the "competent technician" phase in a week of lessons. Assuming they practice and keep at it, they'll develop the intuition that comes from experience and lets them skip a lot of the first half of the flow chart pointing the way to "correctness". Let's face it: the basics are so basic that they can build most of them into consumer cameras.
Thanks to the tendency of makers to Register® as Trademarks™ the names for Every™ Single® Incremental Feature™ they produce†, there will always be gear questions, even if all of the cameras and lenses on the market evolve to converge on a single design. It's not that I want to encourage gear questions, but they do seem to be unavoidable to an extent.
And there are all sorts of questions left around the business of photography. Sure, they all boil down to "make your customers happy and take in more than you spend", but since 68% of all people owning DSLRs‡ are, or plan to be, professional photographers, we can expect this area to live for a while before it's exhausted.
That still leaves the art, and the means of expressing it. I've been in this game long enough that I can usually tell at a glance how a particular photo was created (or at least posit a reasonable alternative way of arriving at the same result). And I've been around long enough to realise that the "rules" and expectations for contemporary photography change a lot over time—if I were to shoot things today the same way I did in the '80s, I don't know whether my pictures would be seen as ground-breaking, retro in a chic way, or hopelessly old-fashioned. As long as there are changing trends and inexperienced photographers, there will be new questions about technique, lighting, posing (or the lack thereof), et cetera.
My humble opinion is that it's in that area—the area of execution, of "how do I" and lighting diagrams and the like—where this site most closely resembles StackOverflow. Light, colour and perspective are our algorithms, and while there may be the photographic equivalent of Knuth's TAOCP to hand everywhere, that doesn't help the person who looks at (or imagines) the finished product and has no idea where to start.
† To the best of my knowledge, none of those terms are actually trademarks, registered or otherwise. If they are, and I've inadvertently violated your intellectual property, well, all I can say is that I'm sorry... that society has reached this level of idiocy.
‡ I am using Simpson's Law of Extemporaneous Statistics here. ("Oh, people can come up with statistics to prove anything, Kent. 14% of people know that.")