Saying web users should define web standards is like saying laptop users should design CPUs. They lack the expertise to do this meaningfully.
Web authors? Maybe. WHATWG was created specifically because W3C wasn’t really listening to web authors though.
I don’t think there are a lot of scenarios where standards aren’t driven by implementers, though. USB, DRAM, WiFi, all this stuff is defined by implementers.
> WHATWG was created specifically because W3C wasn’t really listening to web authors though.
Rather: WHATWG was founded because the companies developing browsers (in particular Google) believed that what the W3C was working on for XHTML 2.0 was too academic, and went into a different direction than their (i.e. in particular Google's) vision for the web.