We need highly skilled workers. That is an education issue, not a lack of available laborers.
The fewer geniuses argument is an interesting one that is addressed in this Forbes article.
One question that does need to be asked is *how* we need to go about obtaining a higher "genius" level in the world. Is it accomplished by just raw numbers? (I.e. give birth to billions of babies in hopes that one of them might save us?). This would be a sort of random chance approach. Roll the dice enough and hope we land on double sixes. On the other hand, could we focus on nurturing the people we currently have. Maybe we will have few super geniuses, but we could cultivate more highly skilled workers that can do the work necessary to improve our life. Significant advances in science (for example) are usually now accomplished by large groups of people. We don't have the individual contributions as much anymore. This reduces the necessity for individual super genius and gives rise to the effective benefits of collective intellect.