It's better to describe analog and digital electronics as a subset of electronics. For the most part, they look at different domains. Even though they are based upon the same underlying principles, the simplifying assumptions are different. A more dramatic example is with RF electronics. While it may look like you are dealing with the same sort of things as the more common low frequency analog electronics, you are going to have a difficult time coaxing an analog circuit to work in the RF domain.

Contrast that to web developers. They are dealing with very different principles from web browser developers, who are mostly working with different principles than operating system developers, who are working with entirely different principles from those who design hardware. It's not that they are working with a different subset of the same thing because one layer of abstraction is directly on top of the one below it and (ideally) the layers below completely hide how they work from the layers above.