Quality slide film can handle more levels, though over a slightly narrower range. Generally one desires at least 12 bits per colour to represent it. 7 decimal orders of magnitude of range of contrast, which would need at least 24 bits. So there is a lot of information in film. However, not all of it is usable information, which causes the debate about the equivalence in pixels.
Film is made up of chemical grains.
The more you blow up film, the more you start seeing noise caused by those grains, and eventually the very clumping of the grains themselves. Of course some are bothered by the grain more than others. The bank of the Colorado River near Moab, Utah. However with a decent lens you don't have to blow up too much before you see the grain. They are actually more subject because CCDs are currently much smaller than 35mm.