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In a recent commentary, Amann and Rosselló-Mórab summarize how the census of Bacteria and Archaea has changed over time (1). For decades, the number of recognized microbial taxa was underestimated owing to limitations associated with culture-based methods and the rules of nomenclature. The authors describe a "quantum leap" in the estimates of global microbial diversity following advances in high-throughput sequencing technology. Despite this, Amann and Rosselló-Mórab project that a complete census of microbial diversity will be reached within a few years culminating in the lower millions of taxa (1). While perhaps attractively optimistic to some, this presumption is misleading for the following reasons.