When mention the effect of marketing by users, I mean to distinguish that from choosing a language based on its technical merits. There's a certain amount of buzz and bandwagon effect that plays in to the success of popular languages, and, yes, languages like Perl, Tcl, and Python had it too.

That's a different sort of marketing, though, from the buzz created by having famous/respected names attached to the languges, like Go had in Google and Rob Pike.