Several reasons. Digital display like computer projectors have replaced the hassle of slide shows. I love projecting slides but it IS a hassle. The digital version doesn't have the impact, of course, but it's so much easier and, for most people, unfortunately good enough. That's the same thing that's going on generally too.
Originally Posted by Lionel1972
Second, negative films have improved tremendously. Back in the days you mention negative film could give you nice skin tones and maybe a white not-too-blue and not-too-yellow wedding dress if you were lucky, but that was about the extent of their virtues. If you were a pro who needed, say, exact matching for product shots, that required transparency film, careful lighting, test exposures with the same processing, careful filtering etc. Now that's not true either. Negative films are now very, very good, and happen to have far more dynamic range and latitude (another way of saying the same thing really) than transparency film. Finally, for we hobbyists, the disappearance of type R paper and the elevation of the price of Ilfochrome into the stratosphere have pretty much removed the reasonable ways of getting a print from the stuff at home using a totally analog process. If you want a print from a transparency now you either buy some very expensive Ilfochrome supplies and learn to print with it, including contrast masking for many images, or you scan it, one way or another - either YOU scan it or you have it scanned for output by a lab.
I still shoot some in 35mm but only in 35mm so far. I bought a box of 4x5 because the price was right and I plan to buy a v700, but I haven't been that tempted to shoot it yet. It would look gorgeous on the lightbox but until I get the scanner what would I do with it? And once I do, I can scan it and, if I buy an expensive ink jet using expensive inks, make expensive prints that look no better than ones I can make in the darkroom on RA4 paper from negatives for much less money at every step of the process, and with more latitude and dynamic range at the same time.
Don't get me wrong, it may not sound like it but I DO like transparency film. I just understand why it's the fastest disappearing type of film.