There are a couple of other big reasons related to differences between film and digital sensors. First film is much less sensitive to the angle at which light

There are a couple of other big reasons related to differences between film and digital sensors. First film is much less sensitive to the angle at which light strikes it. There are some great, sharp old lens designs from leica, zeiss and others that show heavy light fall off in the corners on digital sensors. This is a big part of why even f1.8 or 2 lenses need to be more complicated. Next film grain itself has sharp edges which effectively sharpens images a bit and also limits the resolution and generally has a pleasing effect when viewed at high magnification. With digital you don't get that and lens flaws get a lot more obvious.