Others have covered the answer quite well.

As a network engineer since the early 1980s, I'm actually a bit surprised that there are that MANY. I would have guessed about 100.

As far as movies being streamed. They are rarely streamed over an incredible distance. Most of the time they are hosted quite close. If you are in a major city, the source is in the same city as you.

There are entire businesses based on keeping content locally cached and they are funded by the content providers.