Google's certainly would be. Microsoft has dumped millions into trying to get Bing to a point where it can even begin to compete with Google—if Google open sourced their code, tons of competitors would crop up trying to take market share.
GitHub would probably have less of a problem with open sourcing their code because their primary value prop isn't that they've built some brilliant software but that they take the bother out of managing your source hosting.
> GitHub would probably have less of a problem with open sourcing their code because their primary value prop isn't that they've built some brilliant software but that they take the bother out of managing your source hosting.
GitHub is making money by selling their proprietary pack to other corporations so they could implement it on their own server. If they release it for free, they wouldn't be able to support free code hosting services and remain profitable.
They're also selling premium plans for the regular users, but I don't think that this gives them enough profit to remain profitable.
GitHub would probably have less of a problem with open sourcing their code because their primary value prop isn't that they've built some brilliant software but that they take the bother out of managing your source hosting.