I'm not sure they do. They are popular at the moment but I think all that will fade away once the IPL gets established and the cricket will be the focus. When the T20 cup started in England they did all the dancers and bumpf (ok, not to the same level) and they found out it doesn't really add anything and people aren't really interested in it, they come for the cricket.
Look at any big sporting event, like the Olympics, is anyone really interested in the opening ceremony? We watch it because we are excited about the olympics. Would we care if it wasn't there - no.
Good point Kev. Still the opening Ceremony does add some pizzaz. It gets you in the mood. I agree it's no substitute for the event itself; it's more like the forplay to sex.