I read somewhere on mailing list that there are about ~30 people inside Google working full time on Go. And that is different from engineers working on products built using Go.
With infrastructure cost added it would be easily $10 million a year.
So these Linkedin/Twitter style thought leaders demanding some kinda OpenGo foundation need to ask if they have capacity to raise this amount consistently over years to start and run this foundation.
A foundation doesn't need to replace all the corporate money. At minimum, it's a guarantee that the language will be maintained if/when the corporate entity loses interest. Maintaining a language is not nearly as cumbersome as improving it.
At best, a foundation is also going to provide more neutral governance, as well as a nexus for multiple corporations to work on the language together. Other companies are more likely to adopt Go if they see it as not just a Google project.
I personally don't care whether my favorite languages have a foundation, as long as they're used for large projects by large companies. That alone is a good guarantee that they'll stick around.
So these Linkedin/Twitter style thought leaders demanding some kinda OpenGo foundation need to ask if they have capacity to raise this amount consistently over years to start and run this foundation.