Well, Disney is a publicly-traded company, so we know that Disney's stocks fell by 1.9% since they made the decision to suspend Jimmy Kimmel. And we also know that 1.9% of Disney stock is worth $3.87 billion. We don't know if the Disney boycott was the reason their stocks fell...but evidently Disney does believe it, because they reversed their decision after just one week.
If their change of direction is indeed because of the boycott, it would make this the first ever successful boycott against The Mouse.