One of the main drivers of revenue for Microsoft is Office 365, with 23.1 million subscribers[0]. Along with Azure, MS runs some of the largest web services around. Most developers at MS don't necessarily work on these products, but to say that all the devs working on them use a simple .NET stack + SQL Server is discrediting a lot of work that they do.
Disclaimer: I work for Microsoft in the Office division and opinions are my own
Disclaimer: I work at Google.