Why does Unity not support in-editor/component patch updating?

Pretty much the Titile. If that wasn't clear enough, I'm questioning Unitys system of requiring a full download and install on each update rather than releasing its updates as components. Well I'm sure there's a reason behind it, my internet limitations means that its somewhat difficult to do so on every update, and for a program in this day and age I just cant see why it's not a supported/included feature.