No theory necessary. Out of a population of about 350 million, there are about 600,000 persons who go missing annually. This is a probability rate of 0.0017143/year. For a population sample of about 20,000 (the estimated size of the technical community from which these people came), there would be expected 34 disappearances/year. The subject list is barely more than a dozen over 3 or 4 years. It is nothing but happenstance. The only question might be why there are so few missing persons...but you can't blame that on mysterious actors.