Demand Determines Supply!" Isn't that fact the main tier of business at all?
I believe this certainly plays a large part in it, though I don't think it's the only factor governing this. I think cost, effort and time are also involved.
I could be totally wrong here, but I think that as much as demand dictates supply, we the consumers are dependent on the companies which produce and distribute media content to provide us with a product. What I feel makes this different from other consumer markets is that we don't know exactly what we want. We want "entertainment". It's up to the industry to figure out what that content should consist of.
For reasons I can't fathom, people like reality tv. In this specific situation you have two sources of viable reality tv material. The royal engagement and the Invictus games. It wouldn't be that difficult to sell the games to an audience, but instead the royals are the total focus, while the games were literally reduced to a backdrop.
Here's where I think the money and time comes into the equation. To sell the games, months prior to the event, a production company would need to meet and interview many of the participants, select the ones who have the right "personality". Then they would have to fill out back story (Where did they serve? What branch? How were they wounded? Do they have a family? What is their motivation for wanting to compete in the event? Ect, ect, ect.) giving the audience a reason to emotionally attach to these individual's. Then launch a advertising campaign to entice an audience to watch. The attendance of Prince Harry and his now fiancé at the event could also be used to draw a audience from a wider demographic. There is also an opportunity for merchandising.
This of course takes time, effort and money to prepare. The reasons I think they didn't do this is because the event would be likely seen as a bit of a gamble for a production company. There's the risk that it may not draw an audience and bomb the ratings. (That would be tragic).
It's expensive. If somthing delays the event, that could lose a good portion of viewers who find something else to watch, then forget to check back again. It doesn't have much longevity as it's an annual event. When it ends, the majority of the audience will likely stop following it until the next one.
Now, the Prince and fiancé has upsides that have less to do with consumer demand, but saving money, time and effort.
It's a guaranteed sell. No matter what the occasion, people will buy into it, even if just to scoff at it.
Very little background is needed, the focus being a member of the royal family. Everything about them is aldready public knowledge, so very little information gathering is needed. They can just regurgitate what another "celeb" show already said. There is a fair bit of longevity in the lead up to the wedding. Hell, Prince William and his wife, are still on the cover of at least one magazine every month.
Media content about the royal family, is cheap, easy, quick to produce and financially lucrative. No risk, low cost and high return.
That's why I think the prince completely stole the show, out from his under his own show.
Finally. (Thank god, this was longer than I expected) When faced with the choice of the two reality events. I think our media tells us what we should want to watch, By over hyping one thing, while downplaying another, simply to maximise profit for a bunch of greedy, cheap, shallow media executives.
While we as consumers did indeed ask to be entertained. They tell us what we want to watch for our entertainment, by limiting our choices to whatever makes the most money.
Again, I could be wrong, but that's why I think there is more to it than just supply and demand.