Diversification takes time. In 2011, their non-ads business was about $1 billion / year. That revenue has grown by 60x in 11 years, so about 50%/year growth for more than a decade. For most businesses those numbers are an amazing success story. It's only in comparison to the once-in-a-lifetime search ads business that this would look disappointing.

Microsoft already had diverse businesses 40 years ago, and have "just" needed to maintain that. They're now diverse by default as long as not too many of those existing lines of business fail. No matter how successful a new business of theirs is, it's really hard for it to grow fast enough to threaten that diversity.