The unadvertised mania

I have no knowledge of how ratings and ppv buyrates are predicted based on stats, figures, patterns etc. etc. , anything that can help guide what adds and subtracts to them.   So my question is, for their biggest show of the year, why did the following 3 matches:

Cody vs. Seth

Austin vs. Owens

McMahon vs. Mcaffee 

Were teased, but then atleast two of them were advertised as NOT going to take place as an actual match, only for them to have the match anyway?  Was there an actualy science to why they did what they did?  Was Cody not signed until VERY recently?  Were Austin & McMahon not medically cleared yet or on the fence of performing until day of?

I have no earthly idea why they weren’t just advertised.   Especially the Austin one.