What smd75 is talking about (but doesn't convey well) is the depth of the image. Early digital was strictly 8-bits per pixel, and a very small gamut. RAW gives us 12 to 14 bits of depth per pixel. In cantrast, my 4x5 Provia transparencies, wet-scanned on a drum scanner, give me 16-bits of depth per color channel per pixel: 48 bits per pixel. This lets me get to the detail in zone 2 that's locked up in black on a digital image.
Regarding megapixels, my 4"x5" analog sensor (film) is able to give me the equivalent of about 130 megapixels, and the sensor costs me about $2.25 a sheet.
For comparison, Leaf is selling a 56megapixel camera back for medium format for only $33,000.