An open letter to Google with respect to their new privacy policy and SPYW 14 years ago
First: Google can't just acquire anything. Dropbox and Github both would have to agree to sell their companies to Google first and I don't see either one of them interested in that, especially Github.
Second SPYW doesn't have anything to do with Google buying companies. It's an opt-in program between a company and Google as to how Google can index their site. Because of that, I can't see companies like Dropbox or Github, even if they opted for SPYW to index private information. They would ultimately have control of that.
So basically what I got from the article is that you don't understand SPYW or how acquisitions work...