“Secondly, Apple did not actually ship their Rosetta 2 emulator preinstalled on the Apple Silicon machines but its installation is triggered when the user tries to run an Intel application.”
Apple gave developers a dev kit with an iPad chip and a hint that hardware would ship “by the end of the year.” Mozilla had to guess the date. Then Rosetta turned out not to be preinstalled, and triggering its install was unreliable. Apple controls the hardware, the OS and the timeline, and everyone else plans around rumors.