He made the right call by putting the cloud first, that's where real revenue come from.
Nevertheless, let's remind that $MSFT has around 150k employees, where literally thousands are top tier in their position all across the industry.
Isn't the lion's share of MSFT's profits from their traditional OS and Office business units?
That may be, but each incremental dollar of cloud revenue is assigned a much higher multiple by investors because it is growing quickly and seen as being more defensible over the long term.
Check out their Q4 earnings release; Azure and cloud services are the products with highest growth. IIRC While Office desktop is still a major revenue source the market is trending towards Office 365, and Windows is behind cloud services revenue.