The following are the reasons:
Time Difference: USA is behind in time from Japan by 16 hours. Whatever American television (NBC) shows as "live" I already know the results. I knew Naomi Osaka lost her tennis match before their "live" broadcast. I already knew the mighty unbeatable American basketball team lost to France.
American prejudice: The network (NBC) thinks Americans want to watch only American athletes. That is why they are losing the audience. The American public wants to watch and learn about all the athletes. For example, if in an event an American athlete comes in 5th place they will ignore all the other first 4 and starts to interview and tell the life history of the athlete that came is 5th. His/her childhood, how did he/she trained, if he /she brought his/her significant other to the Olympics, and if they slept together before the event.
Unrecognizable events if an American is participant. I watched an athletic event called "Slalom Canoe". I watched it for one hour. (Side bar: Even though I am not an athlete, I have theoretical knowledge about many games and their rules. From Kho Kho to American Football) I had no idea how this game Slalom Canoe is played and how they score points and how they win. They showed for a long time only because some Americans were the contestants. Many Americans went back to sleep.
They will never show any event that Americans are not participating. For example: Field Hockey. Badminton, Handball, Rhythmic Gymnastics, Table Tennis, Trampoline.
Stay Tuned for my next week's blog post. I will repost the blog post I wrote about spectators for the London Olympics in 2012.