To my best knowledge, there is no data evidence that the vaccines do prevent the transmission of the delta and Omicron (Please fix if I was wrong). The effect of reduce the mortality rate is LINEAR. A simple calculation suggests that the LINEAR contribution could be dominate by the transmission...
As discussed and analyses in the below posts, "enough people wearing respirators" could be an equilibrium point of the final social evolution under the selective pressure of COVID-19, because people wearing resprator (and gloves) could block the propagating path of the virus and lead to smarespiratorll R0. https://www.lesswrong.com/posts/oHT2WZxFA9CSPMicb/the-hammer-and-the-mask-a-call-to-action https://www.lesswrong.com/posts/yKYg6D7HNxLuJDcLS/hammer-and-mask-wide-spread-use-of-reusable-particle Could...