I understand your point, but mindshare can be difficult to evaluate. Do you actually know how popular Mojito is? I certainly have noticed the popularity of Meteor - and unpopularity of Mojito - on HN, but how does that translate to the general population of developers?
Mozilla and Yahoo would make a good strategy, considering Google/Mozilla relationship has cooled in recent years.
I like your Github/Meteor suggestion as well, albeit unlikely that either of those companies would take money or influence from Yahoo.
Also don't think Marissa Mayer has the vision for these sort of changes, although hope I'm wrong on this.