It seems incredible in this day and age that they are time-delaying so much. Social media has been great for live and 'event' TV... but NBC don't seem to have realised that and are denying their viewers a chance to join in
It doesn't bother them - they fully realise it - they just don't care.
What matters to them is maximising ratings AND delivering the right demographics for their advertisers. If more of the right people watch tape-delayed (*) than watch live, then they'll tape-delay. Simple as. They have invested so much to get exclusive rights to the Olympics they are squeezing every last cent out of them.
The thing to remember about the US networks is that they aren't networks. They are only on-air in many areas for certain times of the day, with local programming scheduled at other times of the day. If events were networked live during local programme times, some stations wouldn't show the network feed, and would instead show their own programmes, which they sell advertising within rather than than the network. It's a crazy system for major events - but welcome to a fragmented TV system operated by the free market...
At least, unlike Beijing, NBC are now offering live on-line feeds - apart from the ceremonies (which are classed as entertainment rather than sport apparently) - but these are only available to those who get cable internet I believe... No doubt those streams carry advertising.