Y the champions are struggling? I feel the answer is ...
F1 requires the cars to be up to the mark to put up a good show. A small but significant diffuser change in Brawn cars has let them stay ahead of the champions including Ferraris and McLarens. When your car doesnt have in it the power to get past the other car, very little is left with the able drivers. Brawn reached stardom with its sincere effort (for the last one year) in designing its car. (resulting in diffuser change) Other champs are not fast enough as their cars are not fast enough as the Brawns or the Red Bulls.
Once the Ferraris and other champs come out with similar design change to their cars(may be later this year or next year) its gonna be a different ball game. We may see the champs at the other end of the points table.
So far, Button has had his day!!! Thanks to his team principal Mr.Brawn.
Sadly, Narain had an underpowered car which couldnt match his driving skills. I wish he gets back into F1 circuit with a good team and does well.