It looks like this is just measuring the average bitrate that people are streaming at. It won't reflect whether or not someone is capable of watching higher quality streams than Netflix is actually giving them. I don't think their highest quality is more than 6 megabits/sec, and it's only available on certain devices and movies.

The top number might be the most that Netflix needs to stream a video. The numbers are not important, this is more about variance to each other.

It is a gigabit internet service, but there are also people on the free internet plan which is slower.