A lot of the truly huge bandwidth eaters don't have to cross the Atlantic. Heavily used video streaming services almost always have regional servers directly hooked up to major ISPs backbone networks.

Video streaming alone takes up a huge amount of internet traffic (some sources say 65%, others as much as 80%). Each 5 seconds of 1080p Netflix video eats up as much data as a typical non-video web page. 4k video consumes three times as much. When you take this out of the equation, the amount of data that needs to cross the oceans drop to a much more manageable level.

CDNs (content delivery network) also help lower the amount of data that needs to be transmitted. If you've heard of Cloudflare or Akamai, these are services that host web pages, or much of the content on them, at multiple locations across the earth.

This means often-requested data can be loaded from somewhere close to the user for a lot of web pages. These CDNs also help smaller web pages defend against denial of service attacks.