Yeah, they have a crucial job, but I don't think they need worldwide power. The aliens landed in Johannesburg, after all, so I don't have much trouble believing that they were left to deal with it.
Either way, the fact that 20 years has passed and an otherwise amazing thing has become mundane and depressing is part of the point the film is making, I think, and it's one of the things that makes it so interesting. We, the audience, come at it from an entirely different perspective than the people in the film, for whom the amazement has faded, and all that's left in its place is an impossible problem.