I've found it interesting how many people in the Bay Area, particularly veterans of the 90s boom, discount a lot of the ideas pushed by GitHub and 37signals. Anedotally, one of the common responses whenever I reference either company is, "Yeah, but how big is [GitHub|37signals], really?" It's actually somewhat surprising to me how consistently I've encountered this response (so consistent, it feels as if it was distributed like a political talking point). As mentioned in the slides, publicly announced funding definitely serves as a signal, and I haven't heard anyone say that about GitHub since then, though someone said it to me regarding 37signals within the past few months.
What I think it really has to do with is that GitHub seems to make an effort to hire doers, whereas many companies develop processes to deal with non-doers, eg, having staging servers so non-technical staff can check the work of "their" developers. Remote work also doesn't serve the interests of non-doers, since they want to Have Meetings and Make Decisions.