If Microsoft doesn't believe that OpenAI will achieve AGI by 2030 or that there's a chance that OpenAI won't be the premiere AI company in four years, the deal looks less like a lose and more like they are buying their way out of a risky bet. On the other hand, if OpenAI does well, then Microsoft have a 27% stake in the company and that's not nothing.

This looks more like Microsoft ensuring that they'll win, regardless of how OpenAI fairs in the next four to six years.