Microsoft already began the process of open sourcing stuff while Ballmer was CEO. Eg. What would become DotNet Core.
There are a number of other errors in your points. Some public, some not. I encourage you to re-examine what you think to be true.
Look, I agree it was time for Ballmer to retire and I’m glad Satya is CEO, but while he made some miscalculations, he wasn’t the zero some try to make him to be.