Why is Katrina and Saif not coming together onscreen again?

Bollywood babe Katrina Kaif and ‘chote nawab’ Saif Ali Khan made a nice couple in the 2008 blockbuster movie Race. This odd pairing was a hit with the audience and several filmmakers have tried to cast them together since then. There is a report that none of the filmmakers could manage to bring the powerful pair together again.
So, why did they fail to sign them in a film? Does it mean that the filmmakers are in dearth of good scripts? Probably the scripts could not impress both the stars or may be the role was not that impressive as was in Race.
However, the case may be something else too! It is a well-known fact that Katrina is the arch rival of Saif’s girlfriend Kareena Kapoor. So, is it Kareena, who is keeping her beau Saif away from her rival actress Katrina? If this is the case then Saif will be the biggest looser because Katrina is counted as one of the leading ladies in Bollywood now and she has handful of films with other leading heroes. She is young and can work with any lead stars in the industry now.
But the same cannot be said in case of Saif, who has already come a long way and is a father of two teenage kids. Even though he has proved his worth in the industry recently, he cannot be counted among the top stars at present. So, if he denies acting with Katrina at this point of time, he might lose some valuable and important projects, thus harming his acting career.
So, Bebo must grow up and rather help her beau to get some more films even if Katrina is her rival!