The Rio Olympics opening ceremony featured all kinds of fireworks, world-class athletes in every direction and ... a tape-delayed broadcast.
NBC decided to show Friday night's opening ceremony at 8 p.m. ET despite the event kicking off live at 7 p.m. ET. More people home to watch, edit together a better show, avoid any live gaffes, so on and so on. In the end, it was a business decision to reach the largest audience possible. Other events are on tape delays for the same reason. Even if you disagree with the call, you can understand the thought process.