Less conspiratorially, Wired themselves have an article about that: https://www.wired.com/2010/09/wireless-explainer/ https://www.wired.com/2010/09/wireless-exp

Less conspiratorially, Wired themselves have an article about that: https://www.wired.com/2010/09/wireless-explainer/ https://www.wired.com/2010/09/wireless-explainer/ TL;DR because the FCC regulates available frequency bands, and 900MHz, 2.4GHz, and 5GHz were the ones that were 1) the right combination of high enough to be fast and low enough to be energy efficient and easy to generate, and 2) actually available for use at the time.