It's odd to make an investment in a system and then have that system go away. The earliest I knew of this was back in the film days when Canon changed their lens mount from the FD mount to the EOS mount. They bit the bullet and made the change because the Canon engineers were convinced that the narrow diameter of their camera's FD mount would restrict their ability to design fast and long lenses. Rather than compromise on optical performance they instead pissed off the legions of photographers who had made vast investments in bodies and lenses. And they gave Nikon (same basic mount for the last 10,000 years) a goldmine filled with marketing ammunition.
In the long run it proved to be a prescient move as it allowed them a free hand in lens design and allowed for a flexible electronic interface that made their transition from film to digital that much easier.
More recently Olympus orphaned their Four Thirds cameras (the ones with traditional moving mirrors) in favor of a Micro Four Thirds mount, a move necessitated by the change in the way the cameras auto focused and the amount of space between the back of the lenses and the actual sensor. I can't imagine you were a happy camper if you had just migrated to the older system right before the switch and had just sunk significant money into a couple of E-5 bodies and some lenses like the 7-14mm f2.8, the 14-35mm f2.0 and the 35-100mm f2.0. All incredibly good lenses that never worked as well (focusing) with adapters and the newer EM cameras.
While the lenses would likely last for decades and give the same ultra high quality performance you would be stuck with whatever the final and most advanced camera in the system might be. In the case of Olympus it was the E-5 with a 12 megapixel sensor and a few glitches, like a penchant for back and front focusing. If you were hellbent on staying with your system I guess your short term workaround would be to go out and buy as many remaindered cameras bodies as you could so you would always have a workable candidate to put behind the lenses. But you would never be able to take advantage of the advances in sensor design that have occurred since that camera's tenure in the market. Still, if you are willing to deal with manually focusing the lens you could upgrade to the EM-1 family and still use the optics in which you've invested. So, not really a totally orphaned system.
I was an enthusiastic Contax user in the film days and when they finally closed out the Contax RTS iii and it was apparent that no further development of that mount would occur I was stuck with the choice of trying to soldier onward or take my losses and change systems (again). It would be nearly a decade and a half later when those gem like Contax, Zeiss lenses could be used once again on a camera. In this case a Sony A7rii. But even before the end of film snuffed out the Contax line they also changed mounts in mid-stream, from the Y/C mount (Yashica/Contax) to the Contax N mount. Another engineering move to a wider diameter mount.
The latest (and I think most egregious) brand abandonment came last year from Samsung. As recently as 2012 they talked about becoming the number one or two best selling camera company in the world. About two years ago they introduced their flagship camera, the NX-1, along with an assortment of lenses aimed squarely at professionals and hard core hobbyists. They induced thousands of people to trade in their existing (working) cameras as partial trade up to the new system. They spoke in terms of fleshing out the line and going after the "big guys." There were a few stumbles with the NX-1. It used a new video codec that was a real computer basher. Had they stuck with a conventional codec it's entirely possible that they could have given Panasonic's GH4 a real run for the money with video people. In the purely still photography realm the camera, by most accounts, was a stellar performer. The sensor was detailed and relatively low noise. It also boasted dynamic range that was close (but not equal ) to the Sony sensors, and delivered higher resolution.
I worked with a previous generation of Samsung cameras and found their best lenses to be rivals to the very best optics from Canon and Nikon. The two lenses that they delivered with the NX1 camera initially were very well reviewed. So, right up until the day they decided to pull the plug on the whole camera system they were pushing hard to get people to convert. Their campaign "Ditch the DSLR" was a call to move to mirrorless. And then, country by country, they pulled the plug. No more shipments of cameras but at the same time no official announcements. No one outside of Samsung (and perhaps their advertising affiliates) had any idea whether this was just a pause, a retrenchment or what. It turns out that they just made a decision to walk away from the serious camera market and did it in a most disingenuous way. Like a girlfriend of boyfriend who never breaks up with you but never returns your phone calls. Were they kidnapped? Did they perish in a plane crash? Or were they just never that into you?
So, thousands of people bought into the system and invested only to be left at the altar. Now they have a camera which is only useful with proprietary lenses and a group of lenses that is only useful with a proprietary lens mount. I doubt there will be another firmware upgrade for either body or lenses. And all the interchangeable lens bodies below the flagship are also vanishing.
Samsung obviously didn't go out of business. They still sell cellphones and refrigerators and lots of other stuff all over the world. I'm fairly certain that they looked at the trending numbers for the interchangeable lens camera market worldwide and realized that they had just, with much bluster, entered a declining, perhaps dying, market and they made an executive decision to bail early rather than late.
The sad thing is that with the introduction of the NX1 they just seemed to finally get how to make a usable camera. Something ultimately fun to shoot. Of all the events in the last two years that point most vigorously to the death of the camera market overall Samsung's decision to cut and run is probably the most visible.
I understand Samsung's exit. If I could look at all the future marketing numbers and see that in two years the total pie for all interchangeable lens cameras would shrink by over half I think I would also bail, if I weren't one of the two or three front runners. But I think I could have made a much more graceful and less painful exit. And perhaps I would have figured out a way to make the exit less painful for the consumers who had decided to believe in my company and my sales talk.
I was part of an earlier group of Samsung product testers and users in a program called, Imageloggers. I resigned from the program about six months before the NX1 hit the market. I had lost confidence that Samsung understood cameras from a photographer's point of view. Their focus was about interconnectivity ( which should have made one or two other pundits ecstatic....) and less about the traditional attention to haptics and responsiveness that real camera users demand.
Now, they are just another story line about orphaned camera systems. A sad one too. Perhaps the exploding Note 7 phones are just a bit of Karmic revenge...