I am curious if that graph is median or mean, because I know that there are a few thousand (probably tens of thousands) people living in areas where the only unlimited (non satillite) internet costs ~$500 a month.

The requirements for it are (as far as I can tell) met in the areas where the majority of Americans live (NOT necessarily the majority of "city"s).

In the US candidates do not technically need to be affiliated with any party nor even necessarily register with the government beforehand (it is almost Impossible to win without it for anything major), however for everything short of the president (electoral college makes weird) there is a blank spot where you can write a name and vote for that person. It appears to mostly be an American thing that has led to vermin supreme and other jokes.

Does Germany allow write in candidates?