[chas]

Many software developers don't work with FOSS technology at work. I work in embedded systems and much of the library code I work with has been provided by manufacturers of the devices I'm using. I do find bugs in it and report fixes to the library developer, but they often have strange licensing and don't use github (or even public version control) so this work doesn't end up visibly attributed to me in public.

This doesn't mean that the people working in non-web industries "are not playing in the same league" with respect to skill, it just means that they don't have a huge public representation of the work they do.