I read somewhere when talking about this similar topic, there is an incredibly large amount of engineering that goes into building a 100% VF... and if you want 1.0 magnification, even more so. Film cameras like the rebels for instance i believe wasn't a full 100% but the pro style films were... Some theorys could be that digital cameras, even the rebels, have so much technology, so much refinement, that to keep costs down and make the camera somewhat affordable, that is one of the compromises, or else we could see even higher prices to compensate, and secondly, back then it was needed to have full frame VF because there was no LCD to review images at 100%, there also wasn't the market of photographers then that there are now... demand was low, supplies were low... Photography required more skill back then... Digital photography has really made photographers, even pro's, lazy because of the instant gratification of the image. Back then you had to nail the lighting, nail the scene, reshoots were harder, not only did you have to wait for the film to be developed, contacts to be printed, many times that was days later. If it was a paid shoot and you messed up, you had to coordinate to reshoot it on your dime. More people shot on fully auto back then just to save their own butts or carried light meters with them everywhere... So there were fewer photographers buying, cameras lasted longer, and Canon and Nikon really had to make cutting edge cameras (at that time) to entice photographers to splurge on a new camera, especially since 35mm wasn't the norm. Large format and even Medium format was the norm, so Canon and Nikon had to compete squarely against them to prove their gear was worth it to "professional" photographers... It's a different world now, different market and a new boom of photographers.