Valuing async commication more than sync communication may be detrimental to efficiency:
Positive peer pressure makes individuals perform better.
To have someone to proudly present even small achievements to, creates a lot of motivation.
Many ideas arise only when people brainstorm spontanously.
Pair-Programming is emperically proven to improve quality and reduce development time.
When reading most of your article I somewhat get that fuzzy cold feeling that the way github works, would not be equally suited to all varieties of ways people are creative.
There are people that are rather introverted that need silence and no one around bothering them. There are those more extroverted that also need a lot of movement and freedom but most of all an audience. There are visual thinkers, haptic-thinkers and acoustic thinkers. There people that always need a social context, and those that do what ever someone sais.
There are those that are creative when alone in there quiet homes, and those that to thinking mainly while talking to someone else.
I doubt that the guthub model is equally fair on these different cognitive types. I read that Nils Bohr for example was thinking mainly by talking to his students. If some genius like him would apply for a job at github, do you think you could exploit his full potential?
Also many developers I know actually prefer a real, physical office, simply because there is no such thing as "home-office" if you have little children at home.
Any model of collaboration that people want to deploy widely through out our culture, should be compatible to different situations in life persons are in, and should respect the different cognitive type, so that everyone has a fair chance to be productive in respect to his potential, and hey lets put it in a not so different term: happy.
I would not fall of my chair by the shock emerging from the surprise, hearing github consists of high achieving, 20-30 y.o. hackers that do nothing but work all night and that party really hard in between, I am right there? Would
I find that rather excluding, exclusive and maybe arrogant.
I doubt this is the kind of work environment, that is family friendly.