Web cams are designed to send video over the Internet, so the priority for them is to make the image as small as possible - this means quality is important, but not a priority.
Digital Cameras are designed to replace film cameras. There is a reasonable expectation that the photos will be printed. So the priority with digicams is to capture the highest quality possible. The (large) size of the image is not very important, the quality is.
The difference between the two is typically the image sensor used. In Web cams and most camera phones (picture messages also need to be small) a low power
CMOS sensor is used. In Digital cameras, the good ones at least, a
CCD is used.
So, neither of these suck really, they are just designed for different things, however, a CCD in a web cam is generally a good sign, while finding a CMOS in a digital camera is usually a bad one.