The amount of /facepalming in this thread...
BfA was released August 14th 2018 - Essentially, 2 years and a bit over 3 months ago.
Blizzard has already moved far away from their previously desired "Yearly Expansion" model, because it's completely unfeasible and was just shareholders trying to blow smoke up Activision's ass.
Given this, Blizzcon 2022 would be the perfect timing to announce the next expansion they have in development, followed by a half-year of testing for a solid summer 2023 release.