I found the making of videos they have on that page interesting. Basically the OBS are the ones doing the actual filming and broadcasting of all the Olympic events , and then all the broadcasters of the world rebroadcast that. They also provide all the onscreen graphics.
So NBC could send down a tech crew and an uplink truck and we would still get full coverage of the Olympics minus all the color commentary.
The BBC feed for weightlifting has been excellent (and it's a sport that needs it, with more 'meta' strategy than many things), while NBC's coverage has been US-obsessed and tepid-to-awful for pretty much every competition.