|This Fuji X100 is an example of a 3rd-gen mirrorless camera.|
That is actually a ridiculous question. Of coarse it isn't. But it soon may not be as supported as it once was. Unlike other technologies like computers and cellphones, as long as the mechanical parts still work and your sensor is good your camera will be good until it flat dies. Despite what camera manufacturers would like you to believe, you don't have to upgrade your camera with each new iteration. In fact, I am actually 4 years "behind" on my camera tech and I don't give a darn. However, a new age of photographic technology is here and you need to know what is coming before investing new equipment.
If you are new to the DSLR scene or are thinking about jumping in soon, be careful. Higher-end photography is on a technological precipice and we are about to go "3rd-gen". That'a a fancy way of saying that the camera that you are thinking about buying (if it has a mirror) is not going to support the newest lenses here soon. When you buy a camera you are investing in a complete system and you don't want to be stuck with a camera that isn't going to get more lenses. Unless of course you never plan on buying lenses or only buying used lenses off of Ebay.
The problem lies in the R part of the DSLR which stands for Digital Single Lens Reflex. This means that your digital camera has one lens and a mirror that "Reflexes" or moves out of the way of the sensor when you take a photo. More and more cameras are coming out without the mirror part, which means that the lens mount on the camera must be different than the previous generations mount, making it incompatible with legacy lenses.
In a few short days the camera makers will be announcing new cameras/lenses at the most important photography trade show in North America. You can be certain there will be lots of mirrorless "3rd-gen" cameras announce and there will likely be a few that will carry a "Pro" designation. Olympus is rumored to be announcing a "Pro" succesor to the EP-3 for instance.
Sadly, the days of mirror and that characteristic snap sound are coming to an end. I am preparing to make a jump here in a year or two once things really get cranking. To read more about the new generation of cameras check out this link at the StuckInCustoms blog. Before you do, let me know what you think in the comments below.