I'd wager that has something to do with jumping the shark. People feel the need to chat about 10x developers when they don't even agree what a 1x developer is,

I'd wager that has something to do with jumping the shark. People feel the need to chat about 10x developers when they don't even agree what a 1x developer is, and when they do present a definition, that definition is a function of (company, team, project, existing code base) which means there are more possible instances of 1x developers than the amount of developers who have ever lived. Everyone is better off if they just ditch the "10x" which has connotations that programming nerds will latch on to and just use "highly performant dudes".