Fortunately for 2016, the events are in Brazil, so we’ll get things closer to real time. The 2020 Olympics will need a sea change in approach to media coverage, or there will be a lot of unhappy American viewers. By then, I suspect media is going to look a lot different anyway. NBC and the rest will probably have multiple streaming options by then vs traditional broadcast/cable networks. The speed of change in media is going to be great between now and then.
They will still tape delay it. Events generally take place during the day and NBC wants to show the big stuff in prime time so it will be tape delayed. About the best are when the Olympics are in eastern Asia or Australia where morning events show up live in prime time in the US.
NBC hates those because they don't have hours to research the winners and produce their background stories on them for Bob Costas to yap about. If it is live, they don't know who will win and might waste their time producing a heart rending story about how the athlete's sister was eaten by a bear for someone who come in last in the first round and is never seen again.
I can understand NBC's desire to tape everything and then show it later. They can then stick in commercials where there aren't delays in the event. They can skip when the blocks aren't set properly on a sprint and everyone is milling around for ten minutes. They can show two events that are happening at the same time which they can't if they are live. But some time in the future every single event will be available without inane commentary and the viewer will be able to watch handball all day every day if he wants.