Hm, I'll be the asshole and point out something that to me is kind of obvious: Bootstrap isn't mainstream enough to warrant it's own foundation/organization. Just looking at the caliber of other projects that have gone this way (at the top of my head: Apache, Drupal, Django, Zope...) and looking at Boostrap I don't think it's even close to the userbase/clout needed to pull this off. Even the maintainers of those othe…
What do you mean by "not mainstream enough?" Organizations on Github are simply a convenient place to put one or more projects that are collectively worked on by a group of individuals and do not necessarily have a single core maintainer.