The claim was not that VSCode is a better editor than vim or emacs, but rather that "VSCode is the greatest productivity tool in the history of software engineering". To me, the tool that matches that description is the one which most increases the productivity level for the most people. Emacs or Vim might be better at increasing the productivity of a single individual (super huge might here – I personally found VSCode improved my productivity much more than vim ever did), but once you multiply that out by the number of people impacted, I doubt there is much contest.